21137100 has 36 divisors (see below), whose sum is σ = 61157544. Its totient is φ = 5636480.

The previous prime is 21137087. The next prime is 21137107. The reversal of 21137100 is 173112.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21137100.

It is not an unprimeable number, because it can be changed into a prime (21137107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34929 + ... + 35528.

Almost surely, 2^21137100 is an apocalyptic number.

21137100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21137100 is an abundant number, since it is smaller than the sum of its proper divisors (40020444).

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

21137100 is a wasteful number, since it uses less digits than its factorization.

21137100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70474 (or 70467 counting only the distinct ones).

The product of its (nonzero) digits is 42, while the sum is 15.

The square root of 21137100 is about 4597.5101957473. The cubic root of 21137100 is about 276.4915102355.

The spelling of 21137100 in words is "twenty-one million, one hundred thirty-seven thousand, one hundred".