20117521374457 has 8 divisors (see below), whose sum is σ = 21665311496136. Its totient is φ = 18569772463872.

The previous prime is 20117521374421. The next prime is 20117521374469. The reversal of 20117521374457 is 75447312571102.

It can be written as a sum of positive squares in 4 ways, for example, as 10729155740521 + 9388365633936 = 3275539^2 + 3064044^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20117521374457 - 2²³ = 20117512985849 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20117521374457.

It is not an unprimeable number, because it can be changed into a prime (20117521374557) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9285178 + ... + 11244979.

It is an arithmetic number, because the mean of its divisors is an integer number (2708163937017).

Almost surely, 2^{20117521374457} is an apocalyptic number.

It is an amenable number.

20117521374457 is a deficient number, since it is larger than the sum of its proper divisors (1547790121679).

20117521374457 is a wasteful number, since it uses less digits than its factorization.

20117521374457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20605547.

The product of its (nonzero) digits is 1646400, while the sum is 49.

The spelling of 20117521374457 in words is "twenty trillion, one hundred seventeen billion, five hundred twenty-one million, three hundred seventy-four thousand, four hundred fifty-seven".