21450408 has 32 divisors (see below), whose sum is σ = 61287360. Its totient is φ = 6128640.

The previous prime is 21450389. The next prime is 21450431. The reversal of 21450408 is 80405412.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63673 + ... + 64008.

It is an arithmetic number, because the mean of its divisors is an integer number (1915230).

Almost surely, 2^21450408 is an apocalyptic number.

21450408 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21450408 is an abundant number, since it is smaller than the sum of its proper divisors (39836952).

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

21450408 is a wasteful number, since it uses less digits than its factorization.

21450408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127697 (or 127693 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21450408 is about 4631.4585175731. The cubic root of 21450408 is about 277.8509284798.

The spelling of 21450408 in words is "twenty-one million, four hundred fifty thousand, four hundred eight".