661556051015552 has 64 divisors (see below), whose sum is σ = 1643150581280640. Its totient is φ = 257749110781440.

The previous prime is 661556051015549. The next prime is 661556051015597. The reversal of 661556051015552 is 255510150655166.

661556051015552 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 661556051015494 and 661556051015503.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33561072278 + ... + 33561091989.

It is an arithmetic number, because the mean of its divisors is an integer number (25674227832510).

Almost surely, 2^{661556051015552} is an apocalyptic number.

It is an amenable number.

661556051015552 is an abundant number, since it is smaller than the sum of its proper divisors (981594530265088).

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

661556051015552 is a wasteful number, since it uses less digits than its factorization.

661556051015552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67122164299 (or 67122164287 counting only the distinct ones).

The product of its (nonzero) digits is 6750000, while the sum is 53.

The spelling of 661556051015552 in words is "six hundred sixty-one trillion, five hundred fifty-six billion, fifty-one million, fifteen thousand, five hundred fifty-two".