21001010100 has 72 divisors (see below), whose sum is σ = 69443347008. Its totient is φ = 4800230400.

The previous prime is 21001010089. The next prime is 21001010159. The reversal of 21001010100 is 101010012.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

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, 4998141 + ... + 5002340.

Almost surely, 2^21001010100 is an apocalyptic number.

21001010100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001010100 is an abundant number, since it is smaller than the sum of its proper divisors (48442336908).

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

21001010100 is a wasteful number, since it uses less digits than its factorization.

21001010100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10000505 (or 10000498 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 6.

Adding to 21001010100 its reverse (101010012), we get a palindrome (21102020112).

The spelling of 21001010100 in words is "twenty-one billion, one million, ten thousand, one hundred".