821256164 has 12 divisors (see below), whose sum is σ = 1461558000. Its totient is φ = 403668168.

The previous prime is 821256157. The next prime is 821256173. The reversal of 821256164 is 461652128.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1739714 + ... + 1740185.

It is an arithmetic number, because the mean of its divisors is an integer number (121796500).

Almost surely, 2^821256164 is an apocalyptic number.

It is an amenable number.

821256164 is a deficient number, since it is larger than the sum of its proper divisors (640301836).

821256164 is a wasteful number, since it uses less digits than its factorization.

821256164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3479962 (or 3479960 counting only the distinct ones).

The product of its digits is 23040, while the sum is 35.

The square root of 821256164 is about 28657.5673077810. The cubic root of 821256164 is about 936.4678685227.

The spelling of 821256164 in words is "eight hundred twenty-one million, two hundred fifty-six thousand, one hundred sixty-four".