161959971 has 16 divisors (see below), whose sum is σ = 230710400. Its totient is φ = 100761408.

The previous prime is 161959949. The next prime is 161960011. The reversal of 161959971 is 179959161.

It is a happy number.

It is not a de Polignac number, because 161959971 - 2⁷ = 161959843 is a prime.

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 161959971.

It is not an unprimeable number, because it can be changed into a prime (161959921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17386 + ... + 25023.

It is an arithmetic number, because the mean of its divisors is an integer number (14419400).

Almost surely, 2^161959971 is an apocalyptic number.

161959971 is a deficient number, since it is larger than the sum of its proper divisors (68750429).

161959971 is a wasteful number, since it uses less digits than its factorization.

161959971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42498.

The product of its digits is 153090, while the sum is 48.

The square root of 161959971 is about 12726.3494765781. The cubic root of 161959971 is about 545.0912744472.

The spelling of 161959971 in words is "one hundred sixty-one million, nine hundred fifty-nine thousand, nine hundred seventy-one".