817716978 has 48 divisors (see below), whose sum is σ = 1967703840. Its totient is φ = 251602416.

The previous prime is 817716967. The next prime is 817717001. The reversal of 817716978 is 879617718.

It is a super-2 number, since 2×817716978² = 1337322112218904968, 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 23 ways as a sum of consecutive naturals, for example, 35676 + ... + 53927.

It is an arithmetic number, because the mean of its divisors is an integer number (40993830).

Almost surely, 2^817716978 is an apocalyptic number.

817716978 is an abundant number, since it is smaller than the sum of its proper divisors (1149986862).

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

817716978 is a wasteful number, since it uses less digits than its factorization.

817716978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89640 (or 89621 counting only the distinct ones).

The product of its digits is 1185408, while the sum is 54.

The square root of 817716978 is about 28595.7510480141. The cubic root of 817716978 is about 935.1207020055.

The spelling of 817716978 in words is "eight hundred seventeen million, seven hundred sixteen thousand, nine hundred seventy-eight".