161685457 has 8 divisors (see below), whose sum is σ = 165455784. Its totient is φ = 157941888.

The previous prime is 161685451. The next prime is 161685463. The reversal of 161685457 is 754586161.

It is an interprime number because it is at equal distance from previous prime (161685451) and next prime (161685463).

It can be written as a sum of positive squares in 4 ways, for example, as 48986001 + 112699456 = 6999^2 + 10616^2 .

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-161685457 is a prime.

It is a super-2 number, since 2×161685457² = 52284374010597698, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161685451) 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, 5803 + ... + 18895.

It is an arithmetic number, because the mean of its divisors is an integer number (20681973).

Almost surely, 2^161685457 is an apocalyptic number.

It is an amenable number.

161685457 is a deficient number, since it is larger than the sum of its proper divisors (3770327).

161685457 is a wasteful number, since it uses less digits than its factorization.

161685457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13379.

The product of its digits is 201600, while the sum is 43.

The square root of 161685457 is about 12715.5596416359. The cubic root of 161685457 is about 544.7831328608.

The spelling of 161685457 in words is "one hundred sixty-one million, six hundred eighty-five thousand, four hundred fifty-seven".