20421992 has 16 divisors (see below), whose sum is σ = 38687460. Its totient is φ = 10105344.

The previous prime is 20421971. The next prime is 20421997. The reversal of 20421992 is 29912402.

It can be written as a sum of positive squares in 2 ways, for example, as 20376196 + 45796 = 4514^2 + 214^2 .

It is not an unprimeable number, because it can be changed into a prime (20421997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12383 + ... + 13934.

Almost surely, 2^20421992 is an apocalyptic number.

It is an amenable number.

20421992 is a deficient number, since it is larger than the sum of its proper divisors (18265468).

20421992 is a wasteful number, since it uses less digits than its factorization.

20421992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26420 (or 26416 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 20421992 is about 4519.0698157917. The cubic root of 20421992 is about 273.3375939583.

The spelling of 20421992 in words is "twenty million, four hundred twenty-one thousand, nine hundred ninety-two".