21131002320 has 80 divisors (see below), whose sum is σ = 65849213952. Its totient is φ = 5605419520.

The previous prime is 21131002309. The next prime is 21131002331. The reversal of 21131002320 is 2320013112.

It is an interprime number because it is at equal distance from previous prime (21131002309) and next prime (21131002331).

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21131002320.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184647 + ... + 276326.

Almost surely, 2^21131002320 is an apocalyptic number.

21131002320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21131002320 is an abundant number, since it is smaller than the sum of its proper divisors (44718211632).

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

21131002320 is a wasteful number, since it uses less digits than its factorization.

21131002320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461180 (or 461174 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21131002320 its reverse (2320013112), we get a palindrome (23451015432).

The spelling of 21131002320 in words is "twenty-one billion, one hundred thirty-one million, two thousand, three hundred twenty".