661556051015465 has 16 divisors (see below), whose sum is σ = 793981061153280. Its totient is φ = 529168978457280.

The previous prime is 661556051015443. The next prime is 661556051015507. The reversal of 661556051015465 is 564510150655166.

It is not a de Polignac number, because 661556051015465 - 2¹⁸ = 661556050753321 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661556051015465.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1334096720 + ... + 1334592510.

It is an arithmetic number, because the mean of its divisors is an integer number (49623816322080).

Almost surely, 2^{661556051015465} is an apocalyptic number.

It is an amenable number.

661556051015465 is a deficient number, since it is larger than the sum of its proper divisors (132425010137815).

661556051015465 is a wasteful number, since it uses less digits than its factorization.

661556051015465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533512.

The product of its (nonzero) digits is 16200000, while the sum is 56.

The spelling of 661556051015465 in words is "six hundred sixty-one trillion, five hundred fifty-six billion, fifty-one million, fifteen thousand, four hundred sixty-five".