21331242520 has 96 divisors (see below), whose sum is σ = 55865905200. Its totient is φ = 7309032192.

The previous prime is 21331242509. The next prime is 21331242533. The reversal of 21331242520 is 2524213312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5209594 + ... + 5213686.

Almost surely, 2^21331242520 is an apocalyptic number.

21331242520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21331242520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27932952600).

21331242520 is an abundant number, since it is smaller than the sum of its proper divisors (34534662680).

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

21331242520 is a wasteful number, since it uses less digits than its factorization.

21331242520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6777 (or 6766 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

Adding to 21331242520 its reverse (2524213312), we get a palindrome (23855455832).

The spelling of 21331242520 in words is "twenty-one billion, three hundred thirty-one million, two hundred forty-two thousand, five hundred twenty".