640264256365 has 8 divisors (see below), whose sum is σ = 768813125400. Its totient is φ = 511880726592.

The previous prime is 640264256323. The next prime is 640264256369. The reversal of 640264256365 is 563652462046.

It can be written as a sum of positive squares in 4 ways, for example, as 137227275364 + 503036981001 = 370442^2 + 709251^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640264256365 - 2⁷ = 640264256237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640264256369) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41326294 + ... + 41341783.

It is an arithmetic number, because the mean of its divisors is an integer number (96101640675).

Almost surely, 2^640264256365 is an apocalyptic number.

It is an amenable number.

640264256365 is a deficient number, since it is larger than the sum of its proper divisors (128548869035).

640264256365 is a wasteful number, since it uses less digits than its factorization.

640264256365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82669631.

The product of its (nonzero) digits is 6220800, while the sum is 49.

The spelling of 640264256365 in words is "six hundred forty billion, two hundred sixty-four million, two hundred fifty-six thousand, three hundred sixty-five".