161661739 has 2 divisors, whose sum is σ = 161661740. Its totient is φ = 161661738.

The previous prime is 161661707. The next prime is 161661757. The reversal of 161661739 is 937166161.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 161661739 - 2⁵ = 161661707 is a prime.

It is a super-2 number, since 2×161661739² = 52269035713008242, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161671739) 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, 80830869 + 80830870.

It is an arithmetic number, because the mean of its divisors is an integer number (80830870).

Almost surely, 2^161661739 is an apocalyptic number.

161661739 is a deficient number, since it is larger than the sum of its proper divisors (1).

161661739 is an equidigital number, since it uses as much as digits as its factorization.

161661739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40824, while the sum is 40.

The square root of 161661739 is about 12714.6269705407. The cubic root of 161661739 is about 544.7564930742.

The spelling of 161661739 in words is "one hundred sixty-one million, six hundred sixty-one thousand, seven hundred thirty-nine".