18240708557 has 2 divisors, whose sum is σ = 18240708558. Its totient is φ = 18240708556.

The previous prime is 18240708539. The next prime is 18240708581. The reversal of 18240708557 is 75580704281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9986804356 + 8253904201 = 99934^2 + 90851^2 .

It is a cyclic number.

It is not a de Polignac number, because 18240708557 - 2²² = 18236514253 is a prime.

It is a super-2 number, since 2×18240708557² (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 (18240708257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9120354278 + 9120354279.

It is an arithmetic number, because the mean of its divisors is an integer number (9120354279).

Almost surely, 2^18240708557 is an apocalyptic number.

It is an amenable number.

18240708557 is a deficient number, since it is larger than the sum of its proper divisors (1).

18240708557 is an equidigital number, since it uses as much as digits as its factorization.

18240708557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 627200, while the sum is 47.

The spelling of 18240708557 in words is "eighteen billion, two hundred forty million, seven hundred eight thousand, five hundred fifty-seven".