18133779581 has 2 divisors, whose sum is σ = 18133779582. Its totient is φ = 18133779580.

The previous prime is 18133779553. The next prime is 18133779593. The reversal of 18133779581 is 18597733181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13910079481 + 4223700100 = 117941^2 + 64990^2 .

It is a cyclic number.

It is not a de Polignac number, because 18133779581 - 2²⁶ = 18066670717 is a prime.

It is a super-2 number, since 2×18133779581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18133779511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9066889790 + 9066889791.

It is an arithmetic number, because the mean of its divisors is an integer number (9066889791).

Almost surely, 2^18133779581 is an apocalyptic number.

It is an amenable number.

18133779581 is a deficient number, since it is larger than the sum of its proper divisors (1).

18133779581 is an equidigital number, since it uses as much as digits as its factorization.

18133779581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1270080, while the sum is 53.

The spelling of 18133779581 in words is "eighteen billion, one hundred thirty-three million, seven hundred seventy-nine thousand, five hundred eighty-one".