21001112100 has 108 divisors (see below), whose sum is σ = 65855105316. Its totient is φ = 5597890560.

The previous prime is 21001112071. The next prime is 21001112117. The reversal of 21001112100 is 121110012.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 3591365184 + 17409746916 = 59928^2 + 131946^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3302524 + ... + 3308876.

Almost surely, 2^21001112100 is an apocalyptic number.

21001112100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001112100 is an abundant number, since it is smaller than the sum of its proper divisors (44853993216).

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

21001112100 is a wasteful number, since it uses less digits than its factorization.

21001112100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10046 (or 10036 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21001112100 its reverse (121110012), we get a palindrome (21122222112).

It can be divided in two parts, 210011 and 12100, that added together give a triangular number (222111 = T₆₆₆).

The spelling of 21001112100 in words is "twenty-one billion, one million, one hundred twelve thousand, one hundred".