161311690 has 8 divisors (see below), whose sum is σ = 290361060. Its totient is φ = 64524672.

The previous prime is 161311651. The next prime is 161311727. The reversal of 161311690 is 96113161.

It can be written as a sum of positive squares in 2 ways, for example, as 161264601 + 47089 = 12699^2 + 217^2 .

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

It is a super-2 number, since 2×161311690² = 52042922661312200, which contains 22 as substring.

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, 8065575 + ... + 8065594.

Almost surely, 2^161311690 is an apocalyptic number.

161311690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161311690 is a deficient number, since it is larger than the sum of its proper divisors (129049370).

161311690 is a wasteful number, since it uses less digits than its factorization.

161311690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16131176.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 161311690 is about 12700.8539083008. The cubic root of 161311690 is about 544.3630186741.

The spelling of 161311690 in words is "one hundred sixty-one million, three hundred eleven thousand, six hundred ninety".