21961590 has 32 divisors (see below), whose sum is σ = 60238080. Its totient is φ = 5019744.

The previous prime is 21961571. The next prime is 21961601. The reversal of 21961590 is 9516912.

It is a super-2 number, since 2×21961590² = 964622870656200, 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, 52080 + ... + 52499.

It is an arithmetic number, because the mean of its divisors is an integer number (1882440).

Almost surely, 2^21961590 is an apocalyptic number.

21961590 is an abundant number, since it is smaller than the sum of its proper divisors (38276490).

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

21961590 is a wasteful number, since it uses less digits than its factorization.

21961590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104596.

The product of its (nonzero) digits is 4860, while the sum is 33.

The square root of 21961590 is about 4686.3194513392. The cubic root of 21961590 is about 280.0407678735.

The spelling of 21961590 in words is "twenty-one million, nine hundred sixty-one thousand, five hundred ninety".