21712475868 has 96 divisors (see below), whose sum is σ = 52544733696. Its totient is φ = 6974153472.

The previous prime is 21712475861. The next prime is 21712475933. The reversal of 21712475868 is 86857421712.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21712475868.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21712475861) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21433330 + ... + 21434342.

It is an arithmetic number, because the mean of its divisors is an integer number (547340976).

Almost surely, 2^21712475868 is an apocalyptic number.

It is an amenable number.

21712475868 is an abundant number, since it is smaller than the sum of its proper divisors (30832257828).

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

21712475868 is a wasteful number, since it uses less digits than its factorization.

21712475868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1643 (or 1641 counting only the distinct ones).

The product of its digits is 1505280, while the sum is 51.

The spelling of 21712475868 in words is "twenty-one billion, seven hundred twelve million, four hundred seventy-five thousand, eight hundred sixty-eight".