812656840 has 16 divisors (see below), whose sum is σ = 1828477980. Its totient is φ = 325062720.

The previous prime is 812656813. The next prime is 812656843. The reversal of 812656840 is 48656218.

It can be written as a sum of positive squares in 2 ways, for example, as 808947364 + 3709476 = 28442^2 + 1926^2 .

It is a super-2 number, since 2×812656840² = 1320822279197571200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 20316421 = 812656840 / (8 + 1 + 2 + 6 + 5 + 6 + 8 + 4 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 812656793 and 812656802.

It is not an unprimeable number, because it can be changed into a prime (812656843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10158171 + ... + 10158250.

Almost surely, 2^812656840 is an apocalyptic number.

It is an amenable number.

812656840 is an abundant number, since it is smaller than the sum of its proper divisors (1015821140).

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

812656840 is a wasteful number, since it uses less digits than its factorization.

812656840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20316432 (or 20316428 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 40.

The square root of 812656840 is about 28507.1366503197. The cubic root of 812656840 is about 933.1878270901.

The spelling of 812656840 in words is "eight hundred twelve million, six hundred fifty-six thousand, eight hundred forty".