21129632 has 24 divisors (see below), whose sum is σ = 43035300. Its totient is φ = 10200064.

The previous prime is 21129613. The next prime is 21129643. The reversal of 21129632 is 23692112.

It can be written as a sum of positive squares in 2 ways, for example, as 19044496 + 2085136 = 4364^2 + 1444^2 .

It is a super-2 number, since 2×21129632² = 892922696910848, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10457 + ... + 12312.

Almost surely, 2^21129632 is an apocalyptic number.

It is an amenable number.

21129632 is an abundant number, since it is smaller than the sum of its proper divisors (21905668).

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

21129632 is a wasteful number, since it uses less digits than its factorization.

21129632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22808 (or 22800 counting only the distinct ones).

The product of its digits is 1296, while the sum is 26.

The square root of 21129632 is about 4596.6979452646. The cubic root of 21129632 is about 276.4589437714.

It can be divided in two parts, 21 and 129632, that multiplied together give a palindrome (2722272).

The spelling of 21129632 in words is "twenty-one million, one hundred twenty-nine thousand, six hundred thirty-two".