640290311 has 4 divisors (see below), whose sum is σ = 643161792. Its totient is φ = 637418832.

The previous prime is 640290289. The next prime is 640290383. The reversal of 640290311 is 113092046.

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

It is a cyclic number.

It is not a de Polignac number, because 640290311 - 2²⁶ = 573181447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646290311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1435406 + ... + 1435851.

It is an arithmetic number, because the mean of its divisors is an integer number (160790448).

Almost surely, 2^640290311 is an apocalyptic number.

640290311 is a deficient number, since it is larger than the sum of its proper divisors (2871481).

640290311 is a wasteful number, since it uses less digits than its factorization.

640290311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2871480.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 640290311 is about 25303.9584057515. The cubic root of 640290311 is about 861.9041596673.

The spelling of 640290311 in words is "six hundred forty million, two hundred ninety thousand, three hundred eleven".