815972391 has 48 divisors (see below), whose sum is σ = 1321756800. Its totient is φ = 484481088.

The previous prime is 815972383. The next prime is 815972393. The reversal of 815972391 is 193279518.

It is not a de Polignac number, because 815972391 - 2³ = 815972383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815972393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 572706 + ... + 574128.

It is an arithmetic number, because the mean of its divisors is an integer number (27536600).

Almost surely, 2^815972391 is an apocalyptic number.

815972391 is a deficient number, since it is larger than the sum of its proper divisors (505784409).

815972391 is a wasteful number, since it uses less digits than its factorization.

815972391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1497 (or 1468 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 815972391 is about 28565.2304559232. The cubic root of 815972391 is about 934.4552064734.

The spelling of 815972391 in words is "eight hundred fifteen million, nine hundred seventy-two thousand, three hundred ninety-one".