18055529721 has 32 divisors (see below), whose sum is σ = 27036397440. Its totient is φ = 11907864000.

The previous prime is 18055529669. The next prime is 18055529731. The reversal of 18055529721 is 12792555081.

18055529721 is a `hidden beast` number, since 1 + 8 + 0 + 5 + 552 + 97 + 2 + 1 = 666.

It is not a de Polignac number, because 18055529721 - 2¹¹ = 18055527673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18055529731) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4745806 + ... + 4749608.

It is an arithmetic number, because the mean of its divisors is an integer number (844887420).

Almost surely, 2^18055529721 is an apocalyptic number.

It is an amenable number.

18055529721 is a deficient number, since it is larger than the sum of its proper divisors (8980867719).

18055529721 is a wasteful number, since it uses less digits than its factorization.

18055529721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5654 (or 5648 counting only the distinct ones).

The product of its (nonzero) digits is 252000, while the sum is 45.

It can be divided in two parts, 180555 and 29721, that added together give a triangular number (210276 = T₆₄₈).

The spelling of 18055529721 in words is "eighteen billion, fifty-five million, five hundred twenty-nine thousand, seven hundred twenty-one".