21101021228 has 48 divisors (see below), whose sum is σ = 43021359360. Its totient is φ = 8867911104.

The previous prime is 21101021203. The next prime is 21101021243. The reversal of 21101021228 is 82212010112.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4834175 + ... + 4838537.

It is an arithmetic number, because the mean of its divisors is an integer number (896278320).

Almost surely, 2^21101021228 is an apocalyptic number.

21101021228 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21101021228 is an abundant number, since it is smaller than the sum of its proper divisors (21920338132).

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

21101021228 is a wasteful number, since it uses less digits than its factorization.

21101021228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7686 (or 7684 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

The spelling of 21101021228 in words is "twenty-one billion, one hundred one million, twenty-one thousand, two hundred twenty-eight".