640376365 has 4 divisors (see below), whose sum is σ = 768451644. Its totient is φ = 512301088.

The previous prime is 640376351. The next prime is 640376381. The reversal of 640376365 is 563673046.

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 511031236 + 129345129 = 22606^2 + 11373^2 .

It is a cyclic number.

It is not a de Polignac number, because 640376365 - 2⁷ = 640376237 is a prime.

It is a super-2 number, since 2×640376365² = 820163777701226450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent 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, 64037632 + ... + 64037641.

It is an arithmetic number, because the mean of its divisors is an integer number (192112911).

Almost surely, 2^640376365 is an apocalyptic number.

It is an amenable number.

640376365 is a deficient number, since it is larger than the sum of its proper divisors (128075279).

640376365 is a wasteful number, since it uses less digits than its factorization.

640376365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128075278.

The product of its (nonzero) digits is 272160, while the sum is 40.

The square root of 640376365 is about 25305.6587545158. The cubic root of 640376365 is about 861.9427707873.

The spelling of 640376365 in words is "six hundred forty million, three hundred seventy-six thousand, three hundred sixty-five".