21657107 has 8 divisors (see below), whose sum is σ = 22014720. Its totient is φ = 21301960.

The previous prime is 21657067. The next prime is 21657137. The reversal of 21657107 is 70175612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21657107 - 2⁶ = 21657043 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21657107.

It is not an unprimeable number, because it can be changed into a prime (21657137) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25394 + ... + 26232.

It is an arithmetic number, because the mean of its divisors is an integer number (2751840).

Almost surely, 2^21657107 is an apocalyptic number.

21657107 is a deficient number, since it is larger than the sum of its proper divisors (357613).

21657107 is an equidigital number, since it uses as much as digits as its factorization.

21657107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1233.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 21657107 is about 4653.7196950397. The cubic root of 21657107 is about 278.7405466440.

The spelling of 21657107 in words is "twenty-one million, six hundred fifty-seven thousand, one hundred seven".