20257057217 has 4 divisors (see below), whose sum is σ = 21448648836. Its totient is φ = 19065465600.

The previous prime is 20257057189. The next prime is 20257057241. The reversal of 20257057217 is 71275075202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71275075202 = 2 ⋅35637537601.

It can be written as a sum of positive squares in 2 ways, for example, as 14677564801 + 5579492416 = 121151^2 + 74696^2 .

It is a cyclic number.

It is not a de Polignac number, because 20257057217 - 2¹⁴ = 20257040833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20257057417) 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, 595795784 + ... + 595795817.

It is an arithmetic number, because the mean of its divisors is an integer number (5362162209).

Almost surely, 2^20257057217 is an apocalyptic number.

It is an amenable number.

20257057217 is a deficient number, since it is larger than the sum of its proper divisors (1191591619).

20257057217 is a wasteful number, since it uses less digits than its factorization.

20257057217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1191591618.

The product of its (nonzero) digits is 68600, while the sum is 38.

The spelling of 20257057217 in words is "twenty billion, two hundred fifty-seven million, fifty-seven thousand, two hundred seventeen".