21445543556 has 12 divisors (see below), whose sum is σ = 37550210880. Its totient is φ = 10716911880.

The previous prime is 21445543549. The next prime is 21445543573. The reversal of 21445543556 is 65534554412.

It is a super-2 number, since 2×21445543556² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1456736 + ... + 1471383.

It is an arithmetic number, because the mean of its divisors is an integer number (3129184240).

Almost surely, 2^21445543556 is an apocalyptic number.

It is an amenable number.

21445543556 is a deficient number, since it is larger than the sum of its proper divisors (16104667324).

21445543556 is a wasteful number, since it uses less digits than its factorization.

21445543556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2929954 (or 2929952 counting only the distinct ones).

The product of its digits is 1440000, while the sum is 44.

The spelling of 21445543556 in words is "twenty-one billion, four hundred forty-five million, five hundred forty-three thousand, five hundred fifty-six".