820640936 has 8 divisors (see below), whose sum is σ = 1538701770. Its totient is φ = 410320464.

The previous prime is 820640879. The next prime is 820640957. The reversal of 820640936 is 639046028.

It can be written as a sum of positive squares in only one way, i.e., 712356100 + 108284836 = 26690^2 + 10406^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 820640936.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51290051 + ... + 51290066.

Almost surely, 2^820640936 is an apocalyptic number.

It is an amenable number.

820640936 is a deficient number, since it is larger than the sum of its proper divisors (718060834).

820640936 is a wasteful number, since it uses less digits than its factorization.

820640936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102580123 (or 102580119 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 38.

The square root of 820640936 is about 28646.8311685603. The cubic root of 820640936 is about 936.2339645727.

The spelling of 820640936 in words is "eight hundred twenty million, six hundred forty thousand, nine hundred thirty-six".