21538492 has 6 divisors (see below), whose sum is σ = 37692368. Its totient is φ = 10769244.

The previous prime is 21538487. The next prime is 21538493. The reversal of 21538492 is 29483512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21538493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2692308 + ... + 2692315.

Almost surely, 2^21538492 is an apocalyptic number.

It is an amenable number.

21538492 is a deficient number, since it is larger than the sum of its proper divisors (16153876).

21538492 is a wasteful number, since it uses less digits than its factorization.

21538492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5384627 (or 5384625 counting only the distinct ones).

The product of its digits is 17280, while the sum is 34.

The square root of 21538492 is about 4640.9580907395. The cubic root of 21538492 is about 278.2307316219.

The spelling of 21538492 in words is "twenty-one million, five hundred thirty-eight thousand, four hundred ninety-two".