21021432 has 16 divisors (see below), whose sum is σ = 52553640. Its totient is φ = 7007136.

The previous prime is 21021431. The next prime is 21021449. The reversal of 21021432 is 23412012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 437923 + ... + 437970.

Almost surely, 2^21021432 is an apocalyptic number.

It is an amenable number.

21021432 is an abundant number, since it is smaller than the sum of its proper divisors (31532208).

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

21021432 is a wasteful number, since it uses less digits than its factorization.

21021432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 875902 (or 875898 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21021432 is about 4584.9135215400. The cubic root of 21021432 is about 275.9862417002.

Adding to 21021432 its reverse (23412012), we get a palindrome (44433444).

The spelling of 21021432 in words is "twenty-one million, twenty-one thousand, four hundred thirty-two".