256665625465 has 4 divisors (see below), whose sum is σ = 307998750564. Its totient is φ = 205332500368.

The previous prime is 256665625429. The next prime is 256665625493. The reversal of 256665625465 is 564526566652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 56992490361 + 199673135104 = 238731^2 + 446848^2 .

It is a cyclic number.

It is not a de Polignac number, because 256665625465 - 2¹⁹ = 256665101177 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25666562542 + ... + 25666562551.

It is an arithmetic number, because the mean of its divisors is an integer number (76999687641).

Almost surely, 2^256665625465 is an apocalyptic number.

It is an amenable number.

256665625465 is a deficient number, since it is larger than the sum of its proper divisors (51333125099).

256665625465 is an equidigital number, since it uses as much as digits as its factorization.

256665625465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51333125098.

The product of its digits is 77760000, while the sum is 58.

The spelling of 256665625465 in words is "two hundred fifty-six billion, six hundred sixty-five million, six hundred twenty-five thousand, four hundred sixty-five".