820642664 has 32 divisors (see below), whose sum is σ = 1590412800. Its totient is φ = 396567360.

The previous prime is 820642591. The next prime is 820642727. The reversal of 820642664 is 466246028.

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, 245597 + ... + 248915.

It is an arithmetic number, because the mean of its divisors is an integer number (49700400).

Almost surely, 2^820642664 is an apocalyptic number.

It is an amenable number.

820642664 is a deficient number, since it is larger than the sum of its proper divisors (769770136).

820642664 is a wasteful number, since it uses less digits than its factorization.

820642664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4353 (or 4349 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 38.

The square root of 820642664 is about 28646.8613289484. The cubic root of 820642664 is about 936.2346217059.

The spelling of 820642664 in words is "eight hundred twenty million, six hundred forty-two thousand, six hundred sixty-four".