821290920 has 32 divisors (see below), whose sum is σ = 2463873120. Its totient is φ = 219010880.

The previous prime is 821290919. The next prime is 821290957. The reversal of 821290920 is 29092128.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3421926 + ... + 3422165.

It is an arithmetic number, because the mean of its divisors is an integer number (76996035).

Almost surely, 2^821290920 is an apocalyptic number.

It is an amenable number.

821290920 is an abundant number, since it is smaller than the sum of its proper divisors (1642582200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821290920 is a wasteful number, since it uses less digits than its factorization.

821290920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6844105 (or 6844101 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 821290920 is about 28658.1737031514. The cubic root of 821290920 is about 936.4810789433.

The spelling of 821290920 in words is "eight hundred twenty-one million, two hundred ninety thousand, nine hundred twenty".