161577709 has 2 divisors, whose sum is σ = 161577710. Its totient is φ = 161577708.

The previous prime is 161577671. The next prime is 161577721. The reversal of 161577709 is 907775161.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148596100 + 12981609 = 12190^2 + 3603^2 .

It is a cyclic number.

It is not a de Polignac number, because 161577709 - 2²¹ = 159480557 is a prime.

It is a super-3 number, since 3×161577709³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161577749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80788854 + 80788855.

It is an arithmetic number, because the mean of its divisors is an integer number (80788855).

Almost surely, 2^161577709 is an apocalyptic number.

It is an amenable number.

161577709 is a deficient number, since it is larger than the sum of its proper divisors (1).

161577709 is an equidigital number, since it uses as much as digits as its factorization.

161577709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 92610, while the sum is 43.

The square root of 161577709 is about 12711.3220791545. The cubic root of 161577709 is about 544.6620905645.

The spelling of 161577709 in words is "one hundred sixty-one million, five hundred seventy-seven thousand, seven hundred nine".