21215190 has 32 divisors (see below), whose sum is σ = 51755616. Its totient is φ = 5564160.

The previous prime is 21215147. The next prime is 21215203. The reversal of 21215190 is 9151212.

It is a super-2 number, since 2×21215190² = 900168573472200, which contains 22 as substring.

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, 3967 + ... + 7626.

It is an arithmetic number, because the mean of its divisors is an integer number (1617363).

Almost surely, 2^21215190 is an apocalyptic number.

21215190 is an abundant number, since it is smaller than the sum of its proper divisors (30540426).

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

21215190 is a wasteful number, since it uses less digits than its factorization.

21215190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11664.

The product of its (nonzero) digits is 180, while the sum is 21.

The square root of 21215190 is about 4605.9950065105. The cubic root of 21215190 is about 276.8315866451.

The spelling of 21215190 in words is "twenty-one million, two hundred fifteen thousand, one hundred ninety".