20766457 has 4 divisors (see below), whose sum is σ = 20776180. Its totient is φ = 20756736.

The previous prime is 20766451. The next prime is 20766467. The reversal of 20766457 is 75466702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12362256 + 8404201 = 3516^2 + 2899^2 .

It is a cyclic number.

It is not a de Polignac number, because 20766457 - 2⁷ = 20766329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20766451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108 + ... + 6445.

It is an arithmetic number, because the mean of its divisors is an integer number (5194045).

Almost surely, 2^20766457 is an apocalyptic number.

It is an amenable number.

20766457 is a deficient number, since it is larger than the sum of its proper divisors (9723).

20766457 is an equidigital number, since it uses as much as digits as its factorization.

20766457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9722.

The product of its (nonzero) digits is 70560, while the sum is 37.

The square root of 20766457 is about 4557.0228219749. The cubic root of 20766457 is about 274.8658607511.

The spelling of 20766457 in words is "twenty million, seven hundred sixty-six thousand, four hundred fifty-seven".