20421908253 has 6 divisors (see below), whose sum is σ = 29498311934. Its totient is φ = 13614605496.

The previous prime is 20421908237. The next prime is 20421908321. The reversal of 20421908253 is 35280912402.

It is a happy number.

20421908253 is a `hidden beast` number, since 20 + 421 + 90 + 82 + 53 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18220140324 + 2201767929 = 134982^2 + 46923^2 .

It is not a de Polignac number, because 20421908253 - 2⁴ = 20421908237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421908233) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1134550450 + ... + 1134550467.

Almost surely, 2^20421908253 is an apocalyptic number.

It is an amenable number.

20421908253 is a deficient number, since it is larger than the sum of its proper divisors (9076403681).

20421908253 is a wasteful number, since it uses less digits than its factorization.

20421908253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2269100923 (or 2269100920 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 20421908253 in words is "twenty billion, four hundred twenty-one million, nine hundred eight thousand, two hundred fifty-three".