161312405 has 8 divisors (see below), whose sum is σ = 204961752. Its totient is φ = 121458688.

The previous prime is 161312401. The next prime is 161312509. The reversal of 161312405 is 504213161.

It can be written as a sum of positive squares in 4 ways, for example, as 54272689 + 107039716 = 7367^2 + 10346^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161312405 - 2² = 161312401 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161312401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 948812 + ... + 948981.

It is an arithmetic number, because the mean of its divisors is an integer number (25620219).

Almost surely, 2^161312405 is an apocalyptic number.

It is an amenable number.

161312405 is a deficient number, since it is larger than the sum of its proper divisors (43649347).

161312405 is a wasteful number, since it uses less digits than its factorization.

161312405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1897815.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 161312405 is about 12700.8820559834. The cubic root of 161312405 is about 544.3638229535.

Adding to 161312405 its reverse (504213161), we get a palindrome (665525566).

The spelling of 161312405 in words is "one hundred sixty-one million, three hundred twelve thousand, four hundred five".