640823810 has 16 divisors (see below), whose sum is σ = 1258345152. Its totient is φ = 233026800.

The previous prime is 640823801. The next prime is 640823837. The reversal of 640823810 is 18328046.

It is a super-2 number, since 2×640823810² = 821310310925832200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2912726 + ... + 2912945.

It is an arithmetic number, because the mean of its divisors is an integer number (78646572).

Almost surely, 2^640823810 is an apocalyptic number.

640823810 is a deficient number, since it is larger than the sum of its proper divisors (617521342).

640823810 is a wasteful number, since it uses less digits than its factorization.

640823810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5825689.

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 640823810 is about 25314.4980199095. The cubic root of 640823810 is about 862.1434768164.

The spelling of 640823810 in words is "six hundred forty million, eight hundred twenty-three thousand, eight hundred ten".