21001210022100 has 864 divisors, whose sum is σ = 78978092328576. Its totient is φ = 4259030630400.

The previous prime is 21001210022071. The next prime is 21001210022207. The reversal of 21001210022100 is 122001210012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 1654022952 + ... + 1654035648.

It is an arithmetic number, because the mean of its divisors is an integer number (91409829084).

Almost surely, 2^{21001210022100} is an apocalyptic number.

21001210022100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21001210022100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39489046164288).

21001210022100 is an abundant number, since it is smaller than the sum of its proper divisors (57976882306476).

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

21001210022100 is a wasteful number, since it uses less digits than its factorization.

21001210022100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12985 (or 12971 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21001210022100 its reverse (122001210012), we get a palindrome (21123211232112).

The spelling of 21001210022100 in words is "twenty-one trillion, one billion, two hundred ten million, twenty-two thousand, one hundred".