21422543656 has 16 divisors (see below), whose sum is σ = 40175257140. Its totient is φ = 10709141760.

The previous prime is 21422543651. The next prime is 21422543663. The reversal of 21422543656 is 65634522412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21238398756 + 184144900 = 145734^2 + 13570^2 .

It is not an unprimeable number, because it can be changed into a prime (21422543651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223105 + ... + 304336.

Almost surely, 2^21422543656 is an apocalyptic number.

It is an amenable number.

21422543656 is a deficient number, since it is larger than the sum of its proper divisors (18752713484).

21422543656 is a wasteful number, since it uses less digits than its factorization.

21422543656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 532524 (or 532520 counting only the distinct ones).

The product of its digits is 345600, while the sum is 40.

The spelling of 21422543656 in words is "twenty-one billion, four hundred twenty-two million, five hundred forty-three thousand, six hundred fifty-six".