21000222100 has 72 divisors (see below), whose sum is σ = 53537385888. Its totient is φ = 7049020800.

The previous prime is 21000222071. The next prime is 21000222101. The reversal of 21000222100 is 122200012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000222101) 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, 719974 + ... + 748573.

It is an arithmetic number, because the mean of its divisors is an integer number (743574804).

Almost surely, 2^21000222100 is an apocalyptic number.

21000222100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000222100 is an abundant number, since it is smaller than the sum of its proper divisors (32537163788).

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

21000222100 is a wasteful number, since it uses less digits than its factorization.

21000222100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1468585 (or 1468578 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21000222100 its reverse (122200012), we get a palindrome (21122422112).

The spelling of 21000222100 in words is "twenty-one billion, two hundred twenty-two thousand, one hundred".