21330253504 has 140 divisors (see below), whose sum is σ = 49813163264. Its totient is φ = 9061258752.

The previous prime is 21330253493. The next prime is 21330253517. The reversal of 21330253504 is 40535203312.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 19514782 + ... + 19515874.

Almost surely, 2^21330253504 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21330253504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24906581632).

21330253504 is an abundant number, since it is smaller than the sum of its proper divisors (28482909760).

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

21330253504 is an equidigital number, since it uses as much as digits as its factorization.

21330253504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260 (or 1229 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 28.

Adding to 21330253504 its reverse (40535203312), we get a palindrome (61865456816).

The spelling of 21330253504 in words is "twenty-one billion, three hundred thirty million, two hundred fifty-three thousand, five hundred four".