161161505 has 4 divisors (see below), whose sum is σ = 193393812. Its totient is φ = 128929200.

The previous prime is 161161493. The next prime is 161161519. The reversal of 161161505 is 505161161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 124389409 + 36772096 = 11153^2 + 6064^2 .

It is not a de Polignac number, because 161161505 - 2⁴ = 161161489 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16116146 + ... + 16116155.

It is an arithmetic number, because the mean of its divisors is an integer number (48348453).

Almost surely, 2^161161505 is an apocalyptic number.

It is an amenable number.

161161505 is a deficient number, since it is larger than the sum of its proper divisors (32232307).

161161505 is an equidigital number, since it uses as much as digits as its factorization.

161161505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32232306.

The product of its (nonzero) digits is 900, while the sum is 26.

The square root of 161161505 is about 12694.9401337698. The cubic root of 161161505 is about 544.1940279352.

The spelling of 161161505 in words is "one hundred sixty-one million, one hundred sixty-one thousand, five hundred five".