21431488 has 28 divisors (see below), whose sum is σ = 45801280. Its totient is φ = 9891072.

The previous prime is 21431401. The next prime is 21431489. The reversal of 21431488 is 88413412.

It is not an unprimeable number, because it can be changed into a prime (21431489) 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, 12048 + ... + 13711.

It is an arithmetic number, because the mean of its divisors is an integer number (1635760).

Almost surely, 2^21431488 is an apocalyptic number.

It is an amenable number.

21431488 is an abundant number, since it is smaller than the sum of its proper divisors (24369792).

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

21431488 is a wasteful number, since it uses less digits than its factorization.

21431488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25784 (or 25774 counting only the distinct ones).

The product of its digits is 6144, while the sum is 31.

The square root of 21431488 is about 4629.4155138635. The cubic root of 21431488 is about 277.7692130811.

The spelling of 21431488 in words is "twenty-one million, four hundred thirty-one thousand, four hundred eighty-eight".