21022544656 has 10 divisors (see below), whose sum is σ = 40731180302. Its totient is φ = 10511272320.

The previous prime is 21022544629. The next prime is 21022544681. The reversal of 21022544656 is 65644522012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19259888400 + 1762656256 = 138780^2 + 41984^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 656954505 + ... + 656954536.

Almost surely, 2^21022544656 is an apocalyptic number.

It is an amenable number.

21022544656 is a deficient number, since it is larger than the sum of its proper divisors (19708635646).

21022544656 is a wasteful number, since it uses less digits than its factorization.

21022544656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1313909049 (or 1313909043 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 37.

The spelling of 21022544656 in words is "twenty-one billion, twenty-two million, five hundred forty-four thousand, six hundred fifty-six".