815640819 has 24 divisors (see below), whose sum is σ = 1266275520. Its totient is φ = 465638544.

The previous prime is 815640811. The next prime is 815640857. The reversal of 815640819 is 918046518.

It is not a de Polignac number, because 815640819 - 2³ = 815640811 is a prime.

It is a super-2 number, since 2×815640819² = 1330539891237981522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (815640811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 212572 + ... + 216374.

It is an arithmetic number, because the mean of its divisors is an integer number (52761480).

Almost surely, 2^815640819 is an apocalyptic number.

815640819 is a deficient number, since it is larger than the sum of its proper divisors (450634701).

815640819 is a wasteful number, since it uses less digits than its factorization.

815640819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5279 (or 5272 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 42.

The square root of 815640819 is about 28559.4260971750. The cubic root of 815640819 is about 934.3286167495.

The spelling of 815640819 in words is "eight hundred fifteen million, six hundred forty thousand, eight hundred nineteen".