21101220108 has 72 divisors (see below), whose sum is σ = 56857382400. Its totient is φ = 6579177696.

The previous prime is 21101220103. The next prime is 21101220109. The reversal of 21101220108 is 80102210112.

It is a super-2 number, since 2×21101220108² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21101220103) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 141216 + ... + 249287.

Almost surely, 2^21101220108 is an apocalyptic number.

It is an amenable number.

21101220108 is an abundant number, since it is smaller than the sum of its proper divisors (35756162292).

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

21101220108 is a wasteful number, since it uses less digits than its factorization.

21101220108 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390611 (or 390606 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The spelling of 21101220108 in words is "twenty-one billion, one hundred one million, two hundred twenty thousand, one hundred eight".