161396665 has 8 divisors (see below), whose sum is σ = 194138568. Its totient is φ = 128808960.

The previous prime is 161396663. The next prime is 161396671. The reversal of 161396665 is 566693161.

It can be written as a sum of positive squares in 4 ways, for example, as 15397776 + 145998889 = 3924^2 + 12083^2 .

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

It is not a de Polignac number, because 161396665 - 2¹ = 161396663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161396663) 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, 36232 + ... + 40441.

It is an arithmetic number, because the mean of its divisors is an integer number (24267321).

Almost surely, 2^161396665 is an apocalyptic number.

It is an amenable number.

161396665 is a deficient number, since it is larger than the sum of its proper divisors (32741903).

161396665 is an equidigital number, since it uses as much as digits as its factorization.

161396665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77099.

The product of its digits is 174960, while the sum is 43.

The square root of 161396665 is about 12704.1987153854. The cubic root of 161396665 is about 544.4585875435.

The spelling of 161396665 in words is "one hundred sixty-one million, three hundred ninety-six thousand, six hundred sixty-five".