661313802240 has 1248 divisors, whose sum is σ = 2859400776960. Its totient is φ = 137650765824.

The previous prime is 661313802217. The next prime is 661313802241. The reversal of 661313802240 is 42208313166.

661313802240 is a `hidden beast` number, since 6 + 6 + 1 + 31 + 380 + 2 + 240 = 666.

It is a tau number, because it is divible by the number of its divisors (1248).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 661313802195 and 661313802204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661313802241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1492807459 + ... + 1492807901.

It is an arithmetic number, because the mean of its divisors is an integer number (2291186520).

Almost surely, 2^661313802240 is an apocalyptic number.

661313802240 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661313802240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1429700388480).

661313802240 is an abundant number, since it is smaller than the sum of its proper divisors (2198086974720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661313802240 is a wasteful number, since it uses less digits than its factorization.

661313802240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 587 (or 562 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

It can be divided in two parts, 66131 and 3802240, that added together give a triangular number (3868371 = T₂₇₈₁).

The spelling of 661313802240 in words is "six hundred sixty-one billion, three hundred thirteen million, eight hundred two thousand, two hundred forty".