661461222240 has 576 divisors, whose sum is σ = 2781945129600. Its totient is φ = 139369807872.

The previous prime is 661461222223. The next prime is 661461222283. The reversal of 661461222240 is 42222164166.

661461222240 is a `hidden beast` number, since 6 + 6 + 14 + 612 + 2 + 2 + 24 + 0 = 666.

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 = 661461222195 and 661461222204.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 108629116 + ... + 108635204.

It is an arithmetic number, because the mean of its divisors is an integer number (4829765850).

Almost surely, 2^661461222240 is an apocalyptic number.

661461222240 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 661461222240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1390972564800).

661461222240 is an abundant number, since it is smaller than the sum of its proper divisors (2120483907360).

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

661461222240 is a wasteful number, since it uses less digits than its factorization.

661461222240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6959 (or 6948 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The spelling of 661461222240 in words is "six hundred sixty-one billion, four hundred sixty-one million, two hundred twenty-two thousand, two hundred forty".