21252454520 has 48 divisors (see below), whose sum is σ = 52560317880. Its totient is φ = 7728163520.

The previous prime is 21252454429. The next prime is 21252454529. The reversal of 21252454520 is 2545425212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252454529) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2190662 + ... + 2200341.

Almost surely, 2^21252454520 is an apocalyptic number.

21252454520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21252454520 is an abundant number, since it is smaller than the sum of its proper divisors (31307863360).

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

21252454520 is a wasteful number, since it uses less digits than its factorization.

21252454520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4391036 (or 4391021 counting only the distinct ones).

The product of its (nonzero) digits is 32000, while the sum is 32.

Adding to 21252454520 its reverse (2545425212), we get a palindrome (23797879732).

The spelling of 21252454520 in words is "twenty-one billion, two hundred fifty-two million, four hundred fifty-four thousand, five hundred twenty".