21100221988 has 24 divisors (see below), whose sum is σ = 39257846208. Its totient is φ = 9901004256.

The previous prime is 21100221977. The next prime is 21100221997. The reversal of 21100221988 is 88912200112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2158806 + ... + 2168557.

It is an arithmetic number, because the mean of its divisors is an integer number (1635743592).

Almost surely, 2^21100221988 is an apocalyptic number.

It is an amenable number.

21100221988 is a deficient number, since it is larger than the sum of its proper divisors (18157624220).

21100221988 is a wasteful number, since it uses less digits than its factorization.

21100221988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4327443 (or 4327441 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 34.

The spelling of 21100221988 in words is "twenty-one billion, one hundred million, two hundred twenty-one thousand, nine hundred eighty-eight".