161967971 has 16 divisors (see below), whose sum is σ = 181906560. Its totient is φ = 142941120.

The previous prime is 161967961. The next prime is 161967977. The reversal of 161967971 is 179769161.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161967971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161967977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 83711 + ... + 85623.

It is an arithmetic number, because the mean of its divisors is an integer number (11369160).

Almost surely, 2^161967971 is an apocalyptic number.

161967971 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

161967971 is a deficient number, since it is larger than the sum of its proper divisors (19938589).

161967971 is a wasteful number, since it uses less digits than its factorization.

161967971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2146.

The product of its digits is 142884, while the sum is 47.

The square root of 161967971 is about 12726.6637812115. The cubic root of 161967971 is about 545.1002492129.

The spelling of 161967971 in words is "one hundred sixty-one million, nine hundred sixty-seven thousand, nine hundred seventy-one".