21918597000 has 128 divisors (see below), whose sum is σ = 68439047040. Its totient is φ = 5840428800.

The previous prime is 21918596951. The next prime is 21918597031. The reversal of 21918597000 is 79581912.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5959162 + ... + 5962838.

It is an arithmetic number, because the mean of its divisors is an integer number (534680055).

Almost surely, 2^21918597000 is an apocalyptic number.

21918597000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21918597000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34219523520).

21918597000 is an abundant number, since it is smaller than the sum of its proper divisors (46520450040).

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

21918597000 is a wasteful number, since it uses less digits than its factorization.

21918597000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5688 (or 5674 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 42.

The spelling of 21918597000 in words is "twenty-one billion, nine hundred eighteen million, five hundred ninety-seven thousand".