20968257 has 4 divisors (see below), whose sum is σ = 27957680. Its totient is φ = 13978836.

The previous prime is 20968237. The next prime is 20968271. The reversal of 20968257 is 75286902.

It is a happy number.

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 not a de Polignac number, because 20968257 - 2¹⁵ = 20935489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20968237) 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, 3494707 + ... + 3494712.

It is an arithmetic number, because the mean of its divisors is an integer number (6989420).

Almost surely, 2^20968257 is an apocalyptic number.

It is an amenable number.

20968257 is a deficient number, since it is larger than the sum of its proper divisors (6989423).

20968257 is an equidigital number, since it uses as much as digits as its factorization.

20968257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6989422.

The product of its (nonzero) digits is 60480, while the sum is 39.

The square root of 20968257 is about 4579.1109399096. The cubic root of 20968257 is about 275.7533371726.

The spelling of 20968257 in words is "twenty million, nine hundred sixty-eight thousand, two hundred fifty-seven".