21161590 has 32 divisors (see below), whose sum is σ = 40344480. Its totient is φ = 7977984.

The previous prime is 21161563. The next prime is 21161603. The reversal of 21161590 is 9516112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11622 + ... + 13318.

It is an arithmetic number, because the mean of its divisors is an integer number (1260765).

Almost surely, 2^21161590 is an apocalyptic number.

21161590 is a deficient number, since it is larger than the sum of its proper divisors (19182890).

21161590 is a wasteful number, since it uses less digits than its factorization.

21161590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1776.

The product of its (nonzero) digits is 540, while the sum is 25.

The square root of 21161590 is about 4600.1728228405. The cubic root of 21161590 is about 276.5982524667.

The spelling of 21161590 in words is "twenty-one million, one hundred sixty-one thousand, five hundred ninety".