21431152 has 20 divisors (see below), whose sum is σ = 43965936. Its totient is φ = 10085120.

The previous prime is 21431149. The next prime is 21431161. The reversal of 21431152 is 25113412.

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, 39124 + ... + 39667.

Almost surely, 2^21431152 is an apocalyptic number.

It is an amenable number.

21431152 is an abundant number, since it is smaller than the sum of its proper divisors (22534784).

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

21431152 is a wasteful number, since it uses less digits than its factorization.

21431152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78816 (or 78810 counting only the distinct ones).

The product of its digits is 240, while the sum is 19.

The square root of 21431152 is about 4629.3792240429. The cubic root of 21431152 is about 277.7677614640.

Adding to 21431152 its reverse (25113412), we get a palindrome (46544564).

The spelling of 21431152 in words is "twenty-one million, four hundred thirty-one thousand, one hundred fifty-two".