661185407252160 has 2016 divisors, whose sum is σ = 2899210542171840. Its totient is φ = 137394631213056.

The previous prime is 661185407252129. The next prime is 661185407252173. The reversal of 661185407252160 is 61252704581166.

661185407252160 is a `hidden beast` number, since 6 + 6 + 1 + 1 + 8 + 5 + 40 + 72 + 521 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (2016).

It is a super-2 number, since 2×661185407252160² (a number of 30 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661185407252097 and 661185407252106.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 7242091632 + ... + 7242182928.

Almost surely, 2^{661185407252160} is an apocalyptic number.

661185407252160 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 661185407252160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1449605271085920).

661185407252160 is an abundant number, since it is smaller than the sum of its proper divisors (2238025134919680).

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

661185407252160 is a wasteful number, since it uses less digits than its factorization.

661185407252160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91463 (or 91443 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 54.

The spelling of 661185407252160 in words is "six hundred sixty-one trillion, one hundred eighty-five billion, four hundred seven million, two hundred fifty-two thousand, one hundred sixty".