161696257 has 8 divisors (see below), whose sum is σ = 167884200. Its totient is φ = 155549184.

The previous prime is 161696243. The next prime is 161696287. The reversal of 161696257 is 752696161.

It can be written as a sum of positive squares in 4 ways, for example, as 31371201 + 130325056 = 5601^2 + 11416^2 .

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-161696257 is a prime.

It is a super-2 number, since 2×161696257² = 52291359055620098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161696287) 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, 2032 + ... + 18097.

It is an arithmetic number, because the mean of its divisors is an integer number (20985525).

Almost surely, 2^161696257 is an apocalyptic number.

It is an amenable number.

161696257 is a deficient number, since it is larger than the sum of its proper divisors (6187943).

161696257 is a wasteful number, since it uses less digits than its factorization.

161696257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20435.

The product of its digits is 136080, while the sum is 43.

The square root of 161696257 is about 12715.9843110944. The cubic root of 161696257 is about 544.7952624342.

The spelling of 161696257 in words is "one hundred sixty-one million, six hundred ninety-six thousand, two hundred fifty-seven".