21132424 has 8 divisors (see below), whose sum is σ = 39623310. Its totient is φ = 10566208.

The previous prime is 21132383. The next prime is 21132481. The reversal of 21132424 is 42423112.

It can be written as a sum of positive squares in only one way, i.e., 20520900 + 611524 = 4530^2 + 782^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1320769 + ... + 1320784.

Almost surely, 2^21132424 is an apocalyptic number.

It is an amenable number.

21132424 is a deficient number, since it is larger than the sum of its proper divisors (18490886).

21132424 is a wasteful number, since it uses less digits than its factorization.

21132424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2641559 (or 2641555 counting only the distinct ones).

The product of its digits is 384, while the sum is 19.

The square root of 21132424 is about 4597.0016314985. The cubic root of 21132424 is about 276.4711200267.

Adding to 21132424 its reverse (42423112), we get a palindrome (63555536).

The spelling of 21132424 in words is "twenty-one million, one hundred thirty-two thousand, four hundred twenty-four".