21290332 has 24 divisors (see below), whose sum is σ = 43573376. Its totient is φ = 8911728.

The previous prime is 21290323. The next prime is 21290351. The reversal of 21290332 is 23309212.

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 7 ways as a sum of consecutive naturals, for example, 7638 + ... + 10045.

Almost surely, 2^21290332 is an apocalyptic number.

It is an amenable number.

21290332 is an abundant number, since it is smaller than the sum of its proper divisors (22283044).

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

21290332 is a wasteful number, since it uses less digits than its factorization.

21290332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17737 (or 17735 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 21290332 is about 4614.1447744951. The cubic root of 21290332 is about 277.1580377738.

Adding to 21290332 its reverse (23309212), we get a palindrome (44599544).

The spelling of 21290332 in words is "twenty-one million, two hundred ninety thousand, three hundred thirty-two".