21087408 has 40 divisors (see below), whose sum is σ = 56358000. Its totient is φ = 6786304.

The previous prime is 21087403. The next prime is 21087419. The reversal of 21087408 is 80478012.

It is not an unprimeable number, because it can be changed into a prime (21087401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6183 + ... + 8966.

It is an arithmetic number, because the mean of its divisors is an integer number (1408950).

Almost surely, 2^21087408 is an apocalyptic number.

It is an amenable number.

21087408 is an abundant number, since it is smaller than the sum of its proper divisors (35270592).

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

21087408 is a wasteful number, since it uses less digits than its factorization.

21087408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15189 (or 15183 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 21087408 is about 4592.1027863061. The cubic root of 21087408 is about 276.2746688043.

The spelling of 21087408 in words is "twenty-one million, eighty-seven thousand, four hundred eight".