820004657 has 4 divisors (see below), whose sum is σ = 820085760. Its totient is φ = 819923556.

The previous prime is 820004651. The next prime is 820004683. The reversal of 820004657 is 756400028.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 820004657 - 2⁶ = 820004593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820004651) 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, 22793 + ... + 46470.

It is an arithmetic number, because the mean of its divisors is an integer number (205021440).

Almost surely, 2^820004657 is an apocalyptic number.

It is an amenable number.

820004657 is a deficient number, since it is larger than the sum of its proper divisors (81103).

820004657 is a wasteful number, since it uses less digits than its factorization.

820004657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81102.

The product of its (nonzero) digits is 13440, while the sum is 32.

The square root of 820004657 is about 28635.7234411844. The cubic root of 820004657 is about 935.9919342238.

The spelling of 820004657 in words is "eight hundred twenty million, four thousand, six hundred fifty-seven".