11815820 has 48 divisors (see below), whose sum is σ = 25800768. Its totient is φ = 4542720.

The previous prime is 11815819. The next prime is 11815877. The reversal of 11815820 is 2851811.

It is a super-2 number, since 2×11815820² = 279227204544800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 11815820.

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 15 ways as a sum of consecutive naturals, for example, 75182 + ... + 75338.

It is an arithmetic number, because the mean of its divisors is an integer number (537516).

Almost surely, 2^11815820 is an apocalyptic number.

11815820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11815820 is an abundant number, since it is smaller than the sum of its proper divisors (13984948).

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

11815820 is a wasteful number, since it uses less digits than its factorization.

11815820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290 (or 288 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 26.

The square root of 11815820 is about 3437.4147262150. The cubic root of 11815820 is about 227.7655073479.

The spelling of 11815820 in words is "eleven million, eight hundred fifteen thousand, eight hundred twenty".