161660365 has 4 divisors (see below), whose sum is σ = 193992444. Its totient is φ = 129328288.

The previous prime is 161660357. The next prime is 161660377. The reversal of 161660365 is 563066161.

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 49533444 + 112126921 = 7038^2 + 10589^2 .

It is a cyclic number.

It is not a de Polignac number, because 161660365 - 2³ = 161660357 is a prime.

It is a super-2 number, since 2×161660365² = 52268147223866450, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161660365.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16166032 + ... + 16166041.

It is an arithmetic number, because the mean of its divisors is an integer number (48498111).

Almost surely, 2^161660365 is an apocalyptic number.

It is an amenable number.

161660365 is a deficient number, since it is larger than the sum of its proper divisors (32332079).

161660365 is an equidigital number, since it uses as much as digits as its factorization.

161660365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32332078.

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 161660365 is about 12714.5729381682. The cubic root of 161660365 is about 544.7549497333.

The spelling of 161660365 in words is "one hundred sixty-one million, six hundred sixty thousand, three hundred sixty-five".