161656549 has 2 divisors, whose sum is σ = 161656550. Its totient is φ = 161656548.

The previous prime is 161656531. The next prime is 161656559. The reversal of 161656549 is 945656161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 140588449 + 21068100 = 11857^2 + 4590^2 .

It is a cyclic number.

It is not a de Polignac number, because 161656549 - 2⁹ = 161656037 is a prime.

It is a super-2 number, since 2×161656549² = 52265679669178802, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161656559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80828274 + 80828275.

It is an arithmetic number, because the mean of its divisors is an integer number (80828275).

Almost surely, 2^161656549 is an apocalyptic number.

It is an amenable number.

161656549 is a deficient number, since it is larger than the sum of its proper divisors (1).

161656549 is an equidigital number, since it uses as much as digits as its factorization.

161656549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 194400, while the sum is 43.

The square root of 161656549 is about 12714.4228732570. The cubic root of 161656549 is about 544.7506633780.

The spelling of 161656549 in words is "one hundred sixty-one million, six hundred fifty-six thousand, five hundred forty-nine".