161656555 has 4 divisors (see below), whose sum is σ = 193987872. Its totient is φ = 129325240.

The previous prime is 161656549. The next prime is 161656559. The reversal of 161656555 is 555656161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 555656161 = 1039 ⋅534799.

It is a de Polignac number, because none of the positive numbers 2^k-161656555 is a prime.

It is a super-2 number, since 2×161656555² = 52265683548936050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161656559) 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, 16165651 + ... + 16165660.

It is an arithmetic number, because the mean of its divisors is an integer number (48496968).

Almost surely, 2^161656555 is an apocalyptic number.

161656555 is a deficient number, since it is larger than the sum of its proper divisors (32331317).

161656555 is an equidigital number, since it uses as much as digits as its factorization.

161656555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32331316.

The product of its digits is 135000, while the sum is 40.

The square root of 161656555 is about 12714.4231092095. The cubic root of 161656555 is about 544.7506701177.

The spelling of 161656555 in words is "one hundred sixty-one million, six hundred fifty-six thousand, five hundred fifty-five".