20421708 has 12 divisors (see below), whose sum is σ = 47650680. Its totient is φ = 6807232.

The previous prime is 20421703. The next prime is 20421719. The reversal of 20421708 is 80712402.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (20421703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 850893 + ... + 850916.

It is an arithmetic number, because the mean of its divisors is an integer number (3970890).

Almost surely, 2^20421708 is an apocalyptic number.

It is an amenable number.

20421708 is an abundant number, since it is smaller than the sum of its proper divisors (27228972).

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

20421708 is a wasteful number, since it uses less digits than its factorization.

20421708 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1701816 (or 1701814 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 20421708 is about 4519.0383932868. The cubic root of 20421708 is about 273.3363268890.

It can be divided in two parts, 204 and 21708, that added together give a palindrome (21912).

The spelling of 20421708 in words is "twenty million, four hundred twenty-one thousand, seven hundred eight".