161636691 has 8 divisors (see below), whose sum is σ = 222947280. Its totient is φ = 104041952.

The previous prime is 161636687. The next prime is 161636701. The reversal of 161636691 is 196636161.

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 161636691 - 2² = 161636687 is a prime.

It is a super-2 number, since 2×161636691² = 52252839754858962, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161636611) 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, 928860 + ... + 929033.

It is an arithmetic number, because the mean of its divisors is an integer number (27868410).

Almost surely, 2^161636691 is an apocalyptic number.

161636691 is a deficient number, since it is larger than the sum of its proper divisors (61310589).

161636691 is a wasteful number, since it uses less digits than its factorization.

161636691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1857925.

The product of its digits is 34992, while the sum is 39.

The square root of 161636691 is about 12713.6419251134. The cubic root of 161636691 is about 544.7283566178.

The spelling of 161636691 in words is "one hundred sixty-one million, six hundred thirty-six thousand, six hundred ninety-one".