20257157 has 4 divisors (see below), whose sum is σ = 20751276. Its totient is φ = 19763040.

The previous prime is 20257121. The next prime is 20257163. The reversal of 20257157 is 75175202.

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 10233601 + 10023556 = 3199^2 + 3166^2 .

It is a cyclic number.

It is not a de Polignac number, because 20257157 - 2¹⁶ = 20191621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20257117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 246998 + ... + 247079.

It is an arithmetic number, because the mean of its divisors is an integer number (5187819).

Almost surely, 2^20257157 is an apocalyptic number.

It is an amenable number.

20257157 is a deficient number, since it is larger than the sum of its proper divisors (494119).

20257157 is an equidigital number, since it uses as much as digits as its factorization.

20257157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494118.

The product of its (nonzero) digits is 4900, while the sum is 29.

The square root of 20257157 is about 4500.7951519704. The cubic root of 20257157 is about 272.6001965797.

The spelling of 20257157 in words is "twenty million, two hundred fifty-seven thousand, one hundred fifty-seven".