1815217056 has 36 divisors (see below), whose sum is σ = 5162024322. Its totient is φ = 605072256.

The previous prime is 1815217037. The next prime is 1815217091. The reversal of 1815217056 is 6507125181.

1815217056 is a `hidden beast` number, since 1 + 81 + 521 + 7 + 0 + 56 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1016589456 + 798627600 = 31884^2 + 28260^2 .

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

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1815217056.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 3151131 + ... + 3151706.

Almost surely, 2^1815217056 is an apocalyptic number.

1815217056 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1815217056 is an abundant number, since it is smaller than the sum of its proper divisors (3346807266).

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

1815217056 is a wasteful number, since it uses less digits than its factorization.

1815217056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6302853 (or 6302842 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 36.

The square root of 1815217056 is about 42605.3641693156. The cubic root of 1815217056 is about 1219.8586811137.

The spelling of 1815217056 in words is "one billion, eight hundred fifteen million, two hundred seventeen thousand, fifty-six".