21113100 has 54 divisors (see below), whose sum is σ = 66180660. Its totient is φ = 5629920.

The previous prime is 21113089. The next prime is 21113101. The reversal of 21113100 is 131112.

It is a super-2 number, since 2×21113100² = 891525983220000, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (21113101) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 10830 + ... + 12629.

Almost surely, 2^21113100 is an apocalyptic number.

21113100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21113100 is an abundant number, since it is smaller than the sum of its proper divisors (45067560).

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

21113100 is a wasteful number, since it uses less digits than its factorization.

21113100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23479 (or 23469 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 9.

The square root of 21113100 is about 4594.8993460140. The cubic root of 21113100 is about 276.3868236993.

Adding to 21113100 its reverse (131112), we get a palindrome (21244212).

The spelling of 21113100 in words is "twenty-one million, one hundred thirteen thousand, one hundred".