21055544056 has 8 divisors (see below), whose sum is σ = 39479145120. Its totient is φ = 10527772024.

The previous prime is 21055543969. The next prime is 21055544087. The reversal of 21055544056 is 65044555012.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×21055544056² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1315971496 + ... + 1315971511.

It is an arithmetic number, because the mean of its divisors is an integer number (4934893140).

Almost surely, 2^21055544056 is an apocalyptic number.

It is an amenable number.

21055544056 is a deficient number, since it is larger than the sum of its proper divisors (18423601064).

21055544056 is a wasteful number, since it uses less digits than its factorization.

21055544056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631943013 (or 2631943009 counting only the distinct ones).

The product of its (nonzero) digits is 120000, while the sum is 37.

The spelling of 21055544056 in words is "twenty-one billion, fifty-five million, five hundred forty-four thousand, fifty-six".