21487005918 has 80 divisors (see below), whose sum is σ = 56063288160. Its totient is φ = 6023294784.

The previous prime is 21487005907. The next prime is 21487005923. The reversal of 21487005918 is 81950078412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 118653 + ... + 238856.

It is an arithmetic number, because the mean of its divisors is an integer number (700791102).

Almost surely, 2^21487005918 is an apocalyptic number.

21487005918 is an abundant number, since it is smaller than the sum of its proper divisors (34576282242).

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

21487005918 is a wasteful number, since it uses less digits than its factorization.

21487005918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357583 (or 357574 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 21487005918 in words is "twenty-one billion, four hundred eighty-seven million, five thousand, nine hundred eighteen".