21107100 has 216 divisors, whose sum is σ = 76800640. Its totient is φ = 4371840.

The previous prime is 21107083. The next prime is 21107101. The reversal of 21107100 is 170112.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21107101) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 917689 + ... + 917711.

Almost surely, 2^21107100 is an apocalyptic number.

21107100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21107100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38400320).

21107100 is an abundant number, since it is smaller than the sum of its proper divisors (55693540).

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

21107100 is a wasteful number, since it uses less digits than its factorization.

21107100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89 (or 59 counting only the distinct ones).

The product of its (nonzero) digits is 14, while the sum is 12.

The square root of 21107100 is about 4594.2464017508. The cubic root of 21107100 is about 276.3606396705.

Adding to 21107100 its reverse (170112), we get a palindrome (21277212).

The spelling of 21107100 in words is "twenty-one million, one hundred seven thousand, one hundred".