21508811589018 has 64 divisors (see below), whose sum is σ = 47926624838400. Its totient is φ = 6389554698240.

The previous prime is 21508811589017. The next prime is 21508811589071. The reversal of 21508811589018 is 81098511880512.

It is not an unprimeable number, because it can be changed into a prime (21508811589017) 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, 45295603 + ... + 45767993.

It is an arithmetic number, because the mean of its divisors is an integer number (748853513100).

Almost surely, 2^{21508811589018} is an apocalyptic number.

21508811589018 is an abundant number, since it is smaller than the sum of its proper divisors (26417813249382).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21508811589018 is a wasteful number, since it uses less digits than its factorization.

21508811589018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492567.

The product of its (nonzero) digits is 1843200, while the sum is 57.

The spelling of 21508811589018 in words is "twenty-one trillion, five hundred eight billion, eight hundred eleven million, five hundred eighty-nine thousand, eighteen".