20858717617 has 16 divisors (see below), whose sum is σ = 22158489600. Its totient is φ = 19579553280.

The previous prime is 20858717609. The next prime is 20858717623. The reversal of 20858717617 is 71671785802.

It is a cyclic number.

It is not a de Polignac number, because 20858717617 - 2³ = 20858717609 is a prime.

It is a super-2 number, since 2×20858717617² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20858717017) 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, 1975809 + ... + 1986337.

It is an arithmetic number, because the mean of its divisors is an integer number (1384905600).

Almost surely, 2^20858717617 is an apocalyptic number.

It is an amenable number.

20858717617 is a deficient number, since it is larger than the sum of its proper divisors (1299771983).

20858717617 is a wasteful number, since it uses less digits than its factorization.

20858717617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11496.

The product of its (nonzero) digits is 1317120, while the sum is 52.

The spelling of 20858717617 in words is "twenty billion, eight hundred fifty-eight million, seven hundred seventeen thousand, six hundred seventeen".