161628557 has 2 divisors, whose sum is σ = 161628558. Its totient is φ = 161628556.

The previous prime is 161628479. The next prime is 161628559. The reversal of 161628557 is 755826161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160250281 + 1378276 = 12659^2 + 1174^2 .

It is a cyclic number.

It is not a de Polignac number, because 161628557 - 2⁸ = 161628301 is a prime.

It is a super-2 number, since 2×161628557² = 52247580875804498, which contains 22 as substring.

Together with 161628559, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161628559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80814278 + 80814279.

It is an arithmetic number, because the mean of its divisors is an integer number (80814279).

Almost surely, 2^161628557 is an apocalyptic number.

It is an amenable number.

161628557 is a deficient number, since it is larger than the sum of its proper divisors (1).

161628557 is an equidigital number, since it uses as much as digits as its factorization.

161628557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 100800, while the sum is 41.

The square root of 161628557 is about 12713.3220284865. The cubic root of 161628557 is about 544.7192190580.

The spelling of 161628557 in words is "one hundred sixty-one million, six hundred twenty-eight thousand, five hundred fifty-seven".