20421924 has 12 divisors (see below), whose sum is σ = 47651184. Its totient is φ = 6807304.

The previous prime is 20421899. The next prime is 20421937. The reversal of 20421924 is 42912402.

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

It is a junction number, because it is equal to n+sod(n) for n = 20421894 and 20421903.

It is an unprimeable number.

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, 850902 + ... + 850925.

It is an arithmetic number, because the mean of its divisors is an integer number (3970932).

Almost surely, 2^20421924 is an apocalyptic number.

It is an amenable number.

20421924 is an abundant number, since it is smaller than the sum of its proper divisors (27229260).

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

20421924 is a wasteful number, since it uses less digits than its factorization.

20421924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1701834 (or 1701832 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 20421924 is about 4519.0622921133. The cubic root of 20421924 is about 273.3372905766.

The spelling of 20421924 in words is "twenty million, four hundred twenty-one thousand, nine hundred twenty-four".