21253423260 has 24 divisors (see below), whose sum is σ = 59509585296. Its totient is φ = 5667579520.

The previous prime is 21253423253. The next prime is 21253423271. The reversal of 21253423260 is 6232435212.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 177111801 + ... + 177111920.

It is an arithmetic number, because the mean of its divisors is an integer number (2479566054).

Almost surely, 2^21253423260 is an apocalyptic number.

21253423260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21253423260 is an abundant number, since it is smaller than the sum of its proper divisors (38256162036).

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

21253423260 is a wasteful number, since it uses less digits than its factorization.

21253423260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354223733 (or 354223731 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 30.

Adding to 21253423260 its reverse (6232435212), we get a palindrome (27485858472).

The spelling of 21253423260 in words is "twenty-one billion, two hundred fifty-three million, four hundred twenty-three thousand, two hundred sixty".