21904107 has 4 divisors (see below), whose sum is σ = 29205480. Its totient is φ = 14602736.

The previous prime is 21904087. The next prime is 21904123. The reversal of 21904107 is 70140912.

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

It is a cyclic number.

It is not a de Polignac number, because 21904107 - 2¹⁰ = 21903083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21904607) 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, 3650682 + ... + 3650687.

It is an arithmetic number, because the mean of its divisors is an integer number (7301370).

Almost surely, 2^21904107 is an apocalyptic number.

21904107 is a deficient number, since it is larger than the sum of its proper divisors (7301373).

21904107 is an equidigital number, since it uses as much as digits as its factorization.

21904107 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7301372.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21904107 is about 4680.1823682416. The cubic root of 21904107 is about 279.7962250345.

The spelling of 21904107 in words is "twenty-one million, nine hundred four thousand, one hundred seven".