20511557057017 has 16 divisors (see below), whose sum is σ = 22104428416000. Its totient is φ = 18920840507712.

The previous prime is 20511557056997. The next prime is 20511557057029. The reversal of 20511557057017 is 71075075511502.

It is not a de Polignac number, because 20511557057017 - 2²⁷ = 20511422839289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20511557054017) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 149174623 + ... + 149312059.

It is an arithmetic number, because the mean of its divisors is an integer number (1381526776000).

Almost surely, 2^{20511557057017} is an apocalyptic number.

It is an amenable number.

20511557057017 is a deficient number, since it is larger than the sum of its proper divisors (1592871358983).

20511557057017 is a wasteful number, since it uses less digits than its factorization.

20511557057017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145192.

The product of its (nonzero) digits is 428750, while the sum is 46.

The spelling of 20511557057017 in words is "twenty trillion, five hundred eleven billion, five hundred fifty-seven million, fifty-seven thousand, seventeen".