817979904 has 320 divisors, whose sum is σ = 2828390400. Its totient is φ = 228593664.

The previous prime is 817979893. The next prime is 817979923. The reversal of 817979904 is 409979718.

It is a super-2 number, since 2×817979904² = 1338182246695698432, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7644619 + ... + 7644725.

It is an arithmetic number, because the mean of its divisors is an integer number (8838720).

Almost surely, 2^817979904 is an apocalyptic number.

817979904 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 817979904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1414195200).

817979904 is an abundant number, since it is smaller than the sum of its proper divisors (2010410496).

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

817979904 is a wasteful number, since it uses less digits than its factorization.

817979904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 198 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 54.

The square root of 817979904 is about 28600.3479699111. The cubic root of 817979904 is about 935.2209164665.

The spelling of 817979904 in words is "eight hundred seventeen million, nine hundred seventy-nine thousand, nine hundred four".