161816549553 has 16 divisors (see below), whose sum is σ = 245303298240. Its totient is φ = 105368915232.

The previous prime is 161816549549. The next prime is 161816549579. The reversal of 161816549553 is 355945618161.

It is a happy number.

161816549553 is a `hidden beast` number, since 1 + 6 + 1 + 81 + 6 + 5 + 4 + 9 + 553 = 666.

It is not a de Polignac number, because 161816549553 - 2² = 161816549549 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 161816549553.

It is not an unprimeable number, because it can be changed into a prime (161816549533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 69687276 + ... + 69689597.

It is an arithmetic number, because the mean of its divisors is an integer number (15331456140).

Almost surely, 2^161816549553 is an apocalyptic number.

It is an amenable number.

161816549553 is a deficient number, since it is larger than the sum of its proper divisors (83486748687).

161816549553 is a wasteful number, since it uses less digits than its factorization.

161816549553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139376925 (or 139376919 counting only the distinct ones).

The product of its digits is 3888000, while the sum is 54.

The spelling of 161816549553 in words is "one hundred sixty-one billion, eight hundred sixteen million, five hundred forty-nine thousand, five hundred fifty-three".