20166851689 has 4 divisors (see below), whose sum is σ = 20314055124. Its totient is φ = 20019648256.

The previous prime is 20166851669. The next prime is 20166851759. The reversal of 20166851689 is 98615866102.

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 15740211600 + 4426640089 = 125460^2 + 66533^2 .

It is a cyclic number.

It is not a de Polignac number, because 20166851689 - 2⁷ = 20166851561 is a prime.

It is a super-2 number, since 2×20166851689² (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 (20166851629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73601512 + ... + 73601785.

It is an arithmetic number, because the mean of its divisors is an integer number (5078513781).

Almost surely, 2^20166851689 is an apocalyptic number.

It is an amenable number.

20166851689 is a deficient number, since it is larger than the sum of its proper divisors (147203435).

20166851689 is a wasteful number, since it uses less digits than its factorization.

20166851689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147203434.

The product of its (nonzero) digits is 1244160, while the sum is 52.

The spelling of 20166851689 in words is "twenty billion, one hundred sixty-six million, eight hundred fifty-one thousand, six hundred eighty-nine".