21013144440 has 64 divisors (see below), whose sum is σ = 66747641760. Its totient is φ = 5273886720.

The previous prime is 21013144421. The next prime is 21013144459. The reversal of 21013144440 is 4444131012.

It is an interprime number because it is at equal distance from previous prime (21013144421) and next prime (21013144459).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21013144440.

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, 5148241 + ... + 5152320.

Almost surely, 2^21013144440 is an apocalyptic number.

21013144440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21013144440 is an abundant number, since it is smaller than the sum of its proper divisors (45734497320).

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

21013144440 is a wasteful number, since it uses less digits than its factorization.

21013144440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10300592 (or 10300588 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21013144440 its reverse (4444131012), we get a palindrome (25457275452).

The spelling of 21013144440 in words is "twenty-one billion, thirteen million, one hundred forty-four thousand, four hundred forty".