20457457 has 4 divisors (see below), whose sum is σ = 20537316. Its totient is φ = 20377600.

The previous prime is 20457431. The next prime is 20457461. The reversal of 20457457 is 75475402.

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 9006001 + 11451456 = 3001^2 + 3384^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20457457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20457487) 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 in 3 ways as a sum of consecutive naturals, for example, 39544 + ... + 40057.

It is an arithmetic number, because the mean of its divisors is an integer number (5134329).

Almost surely, 2^20457457 is an apocalyptic number.

It is an amenable number.

20457457 is a deficient number, since it is larger than the sum of its proper divisors (79859).

20457457 is an equidigital number, since it uses as much as digits as its factorization.

20457457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79858.

The product of its (nonzero) digits is 39200, while the sum is 34.

The square root of 20457457 is about 4522.9920406740. The cubic root of 20457457 is about 273.4957292284.

The spelling of 20457457 in words is "twenty million, four hundred fifty-seven thousand, four hundred fifty-seven".