21311313240 has 96 divisors (see below), whose sum is σ = 74372154480. Its totient is φ = 4871155968.

The previous prime is 21311313229. The next prime is 21311313269. The reversal of 21311313240 is 4231311312.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1806307 + ... + 1818066.

Almost surely, 2^21311313240 is an apocalyptic number.

21311313240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21311313240 is an abundant number, since it is smaller than the sum of its proper divisors (53060841240).

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

21311313240 is a wasteful number, since it uses less digits than its factorization.

21311313240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3624401 (or 3624390 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

Adding to 21311313240 its reverse (4231311312), we get a palindrome (25542624552).

The spelling of 21311313240 in words is "twenty-one billion, three hundred eleven million, three hundred thirteen thousand, two hundred forty".