161320381 has 2 divisors, whose sum is σ = 161320382. Its totient is φ = 161320380.

The previous prime is 161320277. The next prime is 161320399. The reversal of 161320381 is 183023161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 101505625 + 59814756 = 10075^2 + 7734^2 .

It is a cyclic number.

It is not a de Polignac number, because 161320381 - 2⁷ = 161320253 is a prime.

It is a super-2 number, since 2×161320381² = 52048530651970322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161320681) 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 as a sum of consecutive naturals, namely, 80660190 + 80660191.

It is an arithmetic number, because the mean of its divisors is an integer number (80660191).

Almost surely, 2^161320381 is an apocalyptic number.

It is an amenable number.

161320381 is a deficient number, since it is larger than the sum of its proper divisors (1).

161320381 is an equidigital number, since it uses as much as digits as its factorization.

161320381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 161320381 is about 12701.1960460423. The cubic root of 161320381 is about 544.3727947253.

The spelling of 161320381 in words is "one hundred sixty-one million, three hundred twenty thousand, three hundred eighty-one".