21000111102 has 48 divisors (see below), whose sum is σ = 45661253040. Its totient is φ = 6975311616.

The previous prime is 21000111091. The next prime is 21000111113. The reversal of 21000111102 is 20111100012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21000111091) and next prime (21000111113).

It is a Harshad number since it is a multiple of its sum of digits (9).

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, 9862774 + ... + 9864902.

It is an arithmetic number, because the mean of its divisors is an integer number (951276105).

Almost surely, 2^21000111102 is an apocalyptic number.

21000111102 is an abundant number, since it is smaller than the sum of its proper divisors (24661141938).

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

21000111102 is a wasteful number, since it uses less digits than its factorization.

21000111102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3817 (or 3814 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21000111102 its reverse (20111100012), we get a palindrome (41111211114).

The spelling of 21000111102 in words is "twenty-one billion, one hundred eleven thousand, one hundred two".