161669961 has 12 divisors (see below), whose sum is σ = 236723188. Its totient is φ = 106303104.

The previous prime is 161669957. The next prime is 161669969. The reversal of 161669961 is 169966161.

It can be written as a sum of positive squares in 2 ways, for example, as 78057225 + 83612736 = 8835^2 + 9144^2 .

It is not a de Polignac number, because 161669961 - 2² = 161669957 is a prime.

It is a super-2 number, since 2×161669961² = 52274352579483042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161669969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 122380 + ... + 123693.

Almost surely, 2^161669961 is an apocalyptic number.

It is an amenable number.

161669961 is a deficient number, since it is larger than the sum of its proper divisors (75053227).

161669961 is a wasteful number, since it uses less digits than its factorization.

161669961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246152 (or 246149 counting only the distinct ones).

The product of its digits is 104976, while the sum is 45.

The square root of 161669961 is about 12714.9502948301. The cubic root of 161669961 is about 544.7657282257.

The spelling of 161669961 in words is "one hundred sixty-one million, six hundred sixty-nine thousand, nine hundred sixty-one".