21564742968 has 64 divisors (see below), whose sum is σ = 63054816000. Its totient is φ = 6809917536.

The previous prime is 21564742963. The next prime is 21564743003. The reversal of 21564742968 is 86924746512.

21564742968 is a `hidden beast` number, since 2 + 1 + 564 + 74 + 2 + 9 + 6 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21564742963) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2623180 + ... + 2631387.

It is an arithmetic number, because the mean of its divisors is an integer number (985231500).

Almost surely, 2^21564742968 is an apocalyptic number.

It is an amenable number.

21564742968 is an abundant number, since it is smaller than the sum of its proper divisors (41490073032).

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

21564742968 is a wasteful number, since it uses less digits than its factorization.

21564742968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5254601 (or 5254591 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 54.

The spelling of 21564742968 in words is "twenty-one billion, five hundred sixty-four million, seven hundred forty-two thousand, nine hundred sixty-eight".