21311163643 has 48 divisors (see below), whose sum is σ = 27402375168. Its totient is φ = 16387728000.

The previous prime is 21311163539. The next prime is 21311163647. The reversal of 21311163643 is 34636111312.

It is not a de Polignac number, because 21311163643 - 2³³ = 12721229051 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21311163647) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14103258 + ... + 14104768.

It is an arithmetic number, because the mean of its divisors is an integer number (570882816).

Almost surely, 2^21311163643 is an apocalyptic number.

21311163643 is a deficient number, since it is larger than the sum of its proper divisors (6091211525).

21311163643 is a wasteful number, since it uses less digits than its factorization.

21311163643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1864 (or 1857 counting only the distinct ones).

The product of its digits is 7776, while the sum is 31.

Adding to 21311163643 its reverse (34636111312), we get a palindrome (55947274955).

The spelling of 21311163643 in words is "twenty-one billion, three hundred eleven million, one hundred sixty-three thousand, six hundred forty-three".