661207566120 has 256 divisors, whose sum is σ = 2056515056640. Its totient is φ = 169939980288.

The previous prime is 661207566101. The next prime is 661207566179. The reversal of 661207566120 is 21665702166.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 260009569 + ... + 260012111.

It is an arithmetic number, because the mean of its divisors is an integer number (8033261940).

Almost surely, 2^661207566120 is an apocalyptic number.

661207566120 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 661207566120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1028257528320).

661207566120 is an abundant number, since it is smaller than the sum of its proper divisors (1395307490520).

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

661207566120 is a wasteful number, since it uses less digits than its factorization.

661207566120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3124 (or 3120 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 42.

The spelling of 661207566120 in words is "six hundred sixty-one billion, two hundred seven million, five hundred sixty-six thousand, one hundred twenty".