21615988718198 has 48 divisors (see below), whose sum is σ = 37808515568304. Its totient is φ = 9241707908160.

The previous prime is 21615988718183. The next prime is 21615988718221. The reversal of 21615988718198 is 89181788951612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 93212240 + ... + 93443852.

It is an arithmetic number, because the mean of its divisors is an integer number (787677407673).

Almost surely, 2^{21615988718198} is an apocalyptic number.

21615988718198 is a deficient number, since it is larger than the sum of its proper divisors (16192526850106).

21615988718198 is a wasteful number, since it uses less digits than its factorization.

21615988718198 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 233917 (or 233910 counting only the distinct ones).

The product of its digits is 139345920, while the sum is 74.

The spelling of 21615988718198 in words is "twenty-one trillion, six hundred fifteen billion, nine hundred eighty-eight million, seven hundred eighteen thousand, one hundred ninety-eight".