21102907 has 4 divisors (see below), whose sum is σ = 24117616. Its totient is φ = 18088200.

The previous prime is 21102883. The next prime is 21102911. The reversal of 21102907 is 70920112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21102907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21102947) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1507344 + ... + 1507357.

It is an arithmetic number, because the mean of its divisors is an integer number (6029404).

Almost surely, 2^21102907 is an apocalyptic number.

21102907 is a deficient number, since it is larger than the sum of its proper divisors (3014709).

21102907 is an equidigital number, since it uses as much as digits as its factorization.

21102907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3014708.

The product of its (nonzero) digits is 252, while the sum is 22.

The square root of 21102907 is about 4593.7900474445. The cubic root of 21102907 is about 276.3423384527.

The spelling of 21102907 in words is "twenty-one million, one hundred two thousand, nine hundred seven".