21056408 has 48 divisors (see below), whose sum is σ = 43616880. Its totient is φ = 9510336.

The previous prime is 21056401. The next prime is 21056437. The reversal of 21056408 is 80465012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 66266 + ... + 66582.

It is an arithmetic number, because the mean of its divisors is an integer number (908685).

Almost surely, 2^21056408 is an apocalyptic number.

It is an amenable number.

21056408 is an abundant number, since it is smaller than the sum of its proper divisors (22560472).

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

21056408 is a wasteful number, since it uses less digits than its factorization.

21056408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384 (or 361 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 21056408 is about 4588.7261849014. The cubic root of 21056408 is about 276.1392212269.

The spelling of 21056408 in words is "twenty-one million, fifty-six thousand, four hundred eight".