20967257 has 4 divisors (see below), whose sum is σ = 20997540. Its totient is φ = 20936976.

The previous prime is 20967227. The next prime is 20967259. The reversal of 20967257 is 75276902.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2785561 + 18181696 = 1669^2 + 4264^2 .

It is a cyclic number.

It is not a de Polignac number, because 20967257 - 2¹⁰ = 20966233 is a prime.

It is a super-2 number, since 2×20967257² = 879251732208098, which contains 22 as substring.

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 20967257.

It is not an unprimeable number, because it can be changed into a prime (20967259) 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, 14078 + ... + 15495.

It is an arithmetic number, because the mean of its divisors is an integer number (5249385).

Almost surely, 2^20967257 is an apocalyptic number.

It is an amenable number.

20967257 is a deficient number, since it is larger than the sum of its proper divisors (30283).

20967257 is an equidigital number, since it uses as much as digits as its factorization.

20967257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30282.

The product of its (nonzero) digits is 52920, while the sum is 38.

The square root of 20967257 is about 4579.0017471060. The cubic root of 20967257 is about 275.7489534396.

The spelling of 20967257 in words is "twenty million, nine hundred sixty-seven thousand, two hundred fifty-seven".