21438496 has 24 divisors (see below), whose sum is σ = 44690940. Its totient is φ = 10088448.

The previous prime is 21438481. The next prime is 21438499. The reversal of 21438496 is 69483412.

It can be written as a sum of positive squares in 2 ways, for example, as 20830096 + 608400 = 4564^2 + 780^2 .

It is a super-2 number, since 2×21438496² = 919218221484032, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21438499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19161 + ... + 20248.

Almost surely, 2^21438496 is an apocalyptic number.

It is an amenable number.

21438496 is an abundant number, since it is smaller than the sum of its proper divisors (23252444).

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

21438496 is a wasteful number, since it uses less digits than its factorization.

21438496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39436 (or 39428 counting only the distinct ones).

The product of its digits is 41472, while the sum is 37.

The square root of 21438496 is about 4630.1723510038. The cubic root of 21438496 is about 277.7994862086.

The spelling of 21438496 in words is "twenty-one million, four hundred thirty-eight thousand, four hundred ninety-six".