20247457 has 2 divisors, whose sum is σ = 20247458. Its totient is φ = 20247456.

The previous prime is 20247449. The next prime is 20247509. The reversal of 20247457 is 75474202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14371681 + 5875776 = 3791^2 + 2424^2 .

It is a cyclic number.

It is not a de Polignac number, because 20247457 - 2³ = 20247449 is a prime.

It is not a weakly prime, because it can be changed into another prime (20247257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10123728 + 10123729.

It is an arithmetic number, because the mean of its divisors is an integer number (10123729).

Almost surely, 2^20247457 is an apocalyptic number.

It is an amenable number.

20247457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20247457 is an equidigital number, since it uses as much as digits as its factorization.

20247457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15680, while the sum is 31.

The square root of 20247457 is about 4499.7174355730. The cubic root of 20247457 is about 272.5566787245.

The spelling of 20247457 in words is "twenty million, two hundred forty-seven thousand, four hundred fifty-seven".