21420588 has 24 divisors (see below), whose sum is σ = 57121792. Its totient is φ = 6120144.

The previous prime is 21420587. The next prime is 21420643. The reversal of 21420588 is 88502412.

It is not an unprimeable number, because it can be changed into a prime (21420587) 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, 127420 + ... + 127587.

Almost surely, 2^21420588 is an apocalyptic number.

21420588 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21420588 is an abundant number, since it is smaller than the sum of its proper divisors (35701204).

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

21420588 is a wasteful number, since it uses less digits than its factorization.

21420588 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255021 (or 255019 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 21420588 is about 4628.2381096914. The cubic root of 21420588 is about 277.7221141916.

It can be divided in two parts, 214 and 20588, that added together give a palindrome (20802).

The spelling of 21420588 in words is "twenty-one million, four hundred twenty thousand, five hundred eighty-eight".