21080408 has 16 divisors (see below), whose sum is σ = 41851080. Its totient is φ = 9920128.

The previous prime is 21080401. The next prime is 21080447. The reversal of 21080408 is 80408012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21080401) 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, 77366 + ... + 77637.

Almost surely, 2^21080408 is an apocalyptic number.

It is an amenable number.

21080408 is a deficient number, since it is larger than the sum of its proper divisors (20770672).

21080408 is a wasteful number, since it uses less digits than its factorization.

21080408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155026 (or 155022 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 21080408 is about 4591.3405449825. The cubic root of 21080408 is about 276.2440954765.

The spelling of 21080408 in words is "twenty-one million, eighty thousand, four hundred eight".