21107604 has 48 divisors (see below), whose sum is σ = 57254400. Its totient is φ = 5927136.

The previous prime is 21107587. The next prime is 21107633. The reversal of 21107604 is 40670112.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2827 + ... + 7085.

It is an arithmetic number, because the mean of its divisors is an integer number (1192800).

Almost surely, 2^21107604 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21107604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28627200).

21107604 is an abundant number, since it is smaller than the sum of its proper divisors (36146796).

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

21107604 is a wasteful number, since it uses less digits than its factorization.

21107604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4332 (or 4330 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 21107604 is about 4594.3012526390. The cubic root of 21107604 is about 276.3628393198.

Adding to 21107604 its reverse (40670112), we get a palindrome (61777716).

The spelling of 21107604 in words is "twenty-one million, one hundred seven thousand, six hundred four".