817891380 has 72 divisors (see below), whose sum is σ = 2483705952. Its totient is φ = 217861056.

The previous prime is 817891363. The next prime is 817891409. The reversal of 817891380 is 83198718.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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, 207387 + ... + 211293.

It is an arithmetic number, because the mean of its divisors is an integer number (34495916).

Almost surely, 2^817891380 is an apocalyptic number.

It is an amenable number.

817891380 is an abundant number, since it is smaller than the sum of its proper divisors (1665814572).

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

817891380 is a wasteful number, since it uses less digits than its factorization.

817891380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5085 (or 5080 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 45.

The square root of 817891380 is about 28598.8003244891. The cubic root of 817891380 is about 935.1871778694.

The spelling of 817891380 in words is "eight hundred seventeen million, eight hundred ninety-one thousand, three hundred eighty".