21814257 has 8 divisors (see below), whose sum is σ = 29121376. Its totient is φ = 14524992.

The previous prime is 21814249. The next prime is 21814277. The reversal of 21814257 is 75241812.

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

It is not a de Polignac number, because 21814257 - 2³ = 21814249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21814237) 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, 1288 + ... + 6729.

It is an arithmetic number, because the mean of its divisors is an integer number (3640172).

Almost surely, 2^21814257 is an apocalyptic number.

It is an amenable number.

21814257 is a deficient number, since it is larger than the sum of its proper divisors (7307119).

21814257 is an equidigital number, since it uses as much as digits as its factorization.

21814257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8927.

The product of its digits is 4480, while the sum is 30.

The square root of 21814257 is about 4670.5735193871. The cubic root of 21814257 is about 279.4131287890.

The spelling of 21814257 in words is "twenty-one million, eight hundred fourteen thousand, two hundred fifty-seven".