21001021102100 has 72 divisors (see below), whose sum is σ = 49088578109088. Its totient is φ = 7752515644800.

The previous prime is 21001021102051. The next prime is 21001021102153. The reversal of 21001021102100 is 120112010012.

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, 4134695 + ... + 7687505.

Almost surely, 2^{21001021102100} is an apocalyptic number.

21001021102100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001021102100 is an abundant number, since it is smaller than the sum of its proper divisors (28087557006988).

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

21001021102100 is a wasteful number, since it uses less digits than its factorization.

21001021102100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3557385 (or 3557378 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21001021102100 its reverse (120112010012), we get a palindrome (21121133112112).

The spelling of 21001021102100 in words is "twenty-one trillion, one billion, twenty-one million, one hundred two thousand, one hundred".