21115590 has 32 divisors (see below), whose sum is σ = 50807520. Its totient is φ = 5616384.

The previous prime is 21115583. The next prime is 21115603. The reversal of 21115590 is 9551112.

It is a self number, because there is not a number n which added to its sum of digits gives 21115590.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16452 + ... + 17688.

It is an arithmetic number, because the mean of its divisors is an integer number (1587735).

Almost surely, 2^21115590 is an apocalyptic number.

21115590 is an abundant number, since it is smaller than the sum of its proper divisors (29691930).

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

21115590 is a wasteful number, since it uses less digits than its factorization.

21115590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1816.

The product of its (nonzero) digits is 450, while the sum is 24.

The square root of 21115590 is about 4595.1702906421. The cubic root of 21115590 is about 276.3976886147.

The spelling of 21115590 in words is "twenty-one million, one hundred fifteen thousand, five hundred ninety".