21010100100 has 72 divisors (see below), whose sum is σ = 66315526368. Its totient is φ = 5093356800.

The previous prime is 21010100087. The next prime is 21010100101. The reversal of 21010100100 is 100101012.

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 not an unprimeable number, because it can be changed into a prime (21010100101) 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, 3180049 + ... + 3186648.

Almost surely, 2^21010100100 is an apocalyptic number.

21010100100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21010100100 is an abundant number, since it is smaller than the sum of its proper divisors (45305426268).

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

21010100100 is a wasteful number, since it uses less digits than its factorization.

21010100100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6366725 (or 6366718 counting only the distinct ones).

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

Adding to 21010100100 its reverse (100101012), we get a palindrome (21110201112).

The spelling of 21010100100 in words is "twenty-one billion, ten million, one hundred thousand, one hundred".