160999981 has 2 divisors, whose sum is σ = 160999982. Its totient is φ = 160999980.

The previous prime is 160999973. The next prime is 160999991. The reversal of 160999981 is 189999061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 101324356 + 59675625 = 10066^2 + 7725^2 .

It is a cyclic number.

It is not a de Polignac number, because 160999981 - 2³ = 160999973 is a prime.

It is a super-2 number, since 2×160999981² = 51841987764000722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (160999991) 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 as a sum of consecutive naturals, namely, 80499990 + 80499991.

It is an arithmetic number, because the mean of its divisors is an integer number (80499991).

Almost surely, 2^160999981 is an apocalyptic number.

It is an amenable number.

160999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

160999981 is an equidigital number, since it uses as much as digits as its factorization.

160999981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 314928, while the sum is 52.

The square root of 160999981 is about 12688.5767917446. The cubic root of 160999981 is about 544.0121611414.

The spelling of 160999981 in words is "one hundred sixty million, nine hundred ninety-nine thousand, nine hundred eighty-one".