661758014776320 has 4224 divisors, whose sum is σ = 3031252623360000. Its totient is φ = 132189113548800.

The previous prime is 661758014776319. The next prime is 661758014776321. The reversal of 661758014776320 is 23677410857166.

661758014776320 is a `hidden beast` number, since 6 + 6 + 1 + 7 + 5 + 80 + 1 + 477 + 63 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (661758014776319) and next prime (661758014776321).

It is a tau number, because it is divible by the number of its divisors (4224).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (661758014776321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 1072541352652 + ... + 1072541353268.

Almost surely, 2^{661758014776320} is an apocalyptic number.

661758014776320 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 661758014776320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1515626311680000).

661758014776320 is an abundant number, since it is smaller than the sum of its proper divisors (2369494608583680).

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

661758014776320 is a wasteful number, since it uses less digits than its factorization.

661758014776320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 910 (or 875 counting only the distinct ones).

The product of its (nonzero) digits is 71124480, while the sum is 63.

The spelling of 661758014776320 in words is "six hundred sixty-one trillion, seven hundred fifty-eight billion, fourteen million, seven hundred seventy-six thousand, three hundred twenty".