640223969 has 32 divisors (see below), whose sum is σ = 815173632. Its totient is φ = 488376000.

The previous prime is 640223957. The next prime is 640223999. The reversal of 640223969 is 969322046.

It is a de Polignac number, because none of the positive numbers 2^k-640223969 is a prime.

It is a super-2 number, since 2×640223969² = 819773460964225922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640223939) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 989204 + ... + 989850.

It is an arithmetic number, because the mean of its divisors is an integer number (25474176).

Almost surely, 2^640223969 is an apocalyptic number.

It is an amenable number.

640223969 is a deficient number, since it is larger than the sum of its proper divisors (174949663).

640223969 is a wasteful number, since it uses less digits than its factorization.

640223969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 917.

The product of its (nonzero) digits is 139968, while the sum is 41.

The square root of 640223969 is about 25302.6474701759. The cubic root of 640223969 is about 861.8743906601.

The spelling of 640223969 in words is "six hundred forty million, two hundred twenty-three thousand, nine hundred sixty-nine".