161557 has 8 divisors (see below), whose sum is σ = 185760. Its totient is φ = 138960.

The previous prime is 161543. The next prime is 161561. The reversal of 161557 is 755161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161557 is a prime.

It is a super-2 number, since 2×161557² = 52201328498, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

161557 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178 + ... + 595.

It is an arithmetic number, because the mean of its divisors is an integer number (23220).

2¹⁶¹⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

161557 is a deficient number, since it is larger than the sum of its proper divisors (24203).

161557 is a wasteful number, since it uses less digits than its factorization.

161557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803.

The product of its digits is 1050, while the sum is 25.

The square root of 161557 is about 401.9415380376. The cubic root of 161557 is about 54.4638820256.

The spelling of 161557 in words is "one hundred sixty-one thousand, five hundred fifty-seven".