11815840 has 24 divisors (see below), whose sum is σ = 27915300. Its totient is φ = 4726272.

The previous prime is 11815819. The next prime is 11815877. The reversal of 11815840 is 4851811.

It can be written as a sum of positive squares in 2 ways, for example, as 11532816 + 283024 = 3396^2 + 532^2 .

It is a super-2 number, since 2×11815840² = 279228149811200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 11815799 and 11815808.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36765 + ... + 37084.

Almost surely, 2^11815840 is an apocalyptic number.

11815840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11815840 is an abundant number, since it is smaller than the sum of its proper divisors (16099460).

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

11815840 is an equidigital number, since it uses as much as digits as its factorization.

11815840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73864 (or 73856 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 28.

The square root of 11815840 is about 3437.4176353769. The cubic root of 11815840 is about 227.7656358566.

It can be divided in two parts, 1181 and 5840, that added together give a triangular number (7021 = T₁₁₈).

The spelling of 11815840 in words is "eleven million, eight hundred fifteen thousand, eight hundred forty".