817731972 has 36 divisors (see below), whose sum is σ = 2156918400. Its totient is φ = 260725872.

The previous prime is 817731947. The next prime is 817731973. The reversal of 817731972 is 279137718.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (817731973) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 492972 + ... + 494627.

It is an arithmetic number, because the mean of its divisors is an integer number (59914400).

Almost surely, 2^817731972 is an apocalyptic number.

It is an amenable number.

817731972 is an abundant number, since it is smaller than the sum of its proper divisors (1339186428).

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

817731972 is a wasteful number, since it uses less digits than its factorization.

817731972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 987632 (or 987627 counting only the distinct ones).

The product of its digits is 148176, while the sum is 45.

The square root of 817731972 is about 28596.0132186289. The cubic root of 817731972 is about 935.1264175585.

The spelling of 817731972 in words is "eight hundred seventeen million, seven hundred thirty-one thousand, nine hundred seventy-two".