21013432 has 16 divisors (see below), whose sum is σ = 42982200. Its totient is φ = 9551520.

The previous prime is 21013427. The next prime is 21013451. The reversal of 21013432 is 23431012.

It is a happy number.

It is a congruent number.

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, 119307 + ... + 119482.

Almost surely, 2^21013432 is an apocalyptic number.

21013432 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21013432 is an abundant number, since it is smaller than the sum of its proper divisors (21968768).

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

21013432 is a wasteful number, since it uses less digits than its factorization.

21013432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238806 (or 238802 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21013432 is about 4584.0410120329. The cubic root of 21013432 is about 275.9512271165.

Adding to 21013432 its reverse (23431012), we get a palindrome (44444444).

The spelling of 21013432 in words is "twenty-one million, thirteen thousand, four hundred thirty-two".