18891958869 has 18 divisors (see below), whose sum is σ = 31743632310. Its totient is φ = 10795404816.

The previous prime is 18891958843. The next prime is 18891958907. The reversal of 18891958869 is 96885919881.

It can be written as a sum of positive squares in only one way, i.e., 16157714769 + 2734244100 = 127113^2 + 52290^2 .

It is not a de Polignac number, because 18891958869 - 2⁷ = 18891958741 is a prime.

It is a super-2 number, since 2×18891958869² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18891958797 and 18891958806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18891958829) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 21419014 + ... + 21419895.

Almost surely, 2^18891958869 is an apocalyptic number.

It is an amenable number.

18891958869 is a deficient number, since it is larger than the sum of its proper divisors (12851673441).

18891958869 is a wasteful number, since it uses less digits than its factorization.

18891958869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42838929 (or 42838919 counting only the distinct ones).

The product of its digits is 89579520, while the sum is 72.

The spelling of 18891958869 in words is "eighteen billion, eight hundred ninety-one million, nine hundred fifty-eight thousand, eight hundred sixty-nine".