16518685957 has 4 divisors (see below), whose sum is σ = 16704289260. Its totient is φ = 16333082656.

The previous prime is 16518685949. The next prime is 16518686003. The reversal of 16518685957 is 75958681561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75958681561 = 7 ⋅10851240223.

It can be written as a sum of positive squares in 2 ways, for example, as 11281413796 + 5237272161 = 106214^2 + 72369^2 .

It is a cyclic number.

It is not a de Polignac number, because 16518685957 - 2³ = 16518685949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16518685895 and 16518685904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16518625957) 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, 92801518 + ... + 92801695.

It is an arithmetic number, because the mean of its divisors is an integer number (4176072315).

Almost surely, 2^16518685957 is an apocalyptic number.

It is an amenable number.

16518685957 is a deficient number, since it is larger than the sum of its proper divisors (185603303).

16518685957 is an equidigital number, since it uses as much as digits as its factorization.

16518685957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185603302.

The product of its digits is 18144000, while the sum is 61.

The spelling of 16518685957 in words is "sixteen billion, five hundred eighteen million, six hundred eighty-five thousand, nine hundred fifty-seven".