21107249 has 4 divisors (see below), whose sum is σ = 21788160. Its totient is φ = 20426340.

The previous prime is 21107243. The next prime is 21107267. The reversal of 21107249 is 94270112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21107249 - 2⁸ = 21106993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21107243) 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, 340409 + ... + 340470.

It is an arithmetic number, because the mean of its divisors is an integer number (5447040).

Almost surely, 2^21107249 is an apocalyptic number.

It is an amenable number.

21107249 is a deficient number, since it is larger than the sum of its proper divisors (680911).

21107249 is an equidigital number, since it uses as much as digits as its factorization.

21107249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680910.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 21107249 is about 4594.2626176569. The cubic root of 21107249 is about 276.3612899673.

The spelling of 21107249 in words is "twenty-one million, one hundred seven thousand, two hundred forty-nine".