163657 has 4 divisors (see below), whose sum is σ = 176260. Its totient is φ = 151056.

The previous prime is 163643. The next prime is 163661. The reversal of 163657 is 756361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 756361 = 271 ⋅2791.

It can be written as a sum of positive squares in 2 ways, for example, as 18496 + 145161 = 136^2 + 381^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-163657 is a prime.

It is a super-2 number, since 2×163657² = 53567227298, which contains 22 as substring.

It is a Duffinian number.

163657 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (163627) 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 in 3 ways as a sum of consecutive naturals, for example, 6282 + ... + 6307.

It is an arithmetic number, because the mean of its divisors is an integer number (44065).

2¹⁶³⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

163657 is a deficient number, since it is larger than the sum of its proper divisors (12603).

163657 is a wasteful number, since it uses less digits than its factorization.

163657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12602.

The product of its digits is 3780, while the sum is 28.

The square root of 163657 is about 404.5454239019. The cubic root of 163657 is about 54.6988499436.

Subtracting 163657 from its reverse (756361), we obtain a cube (592704 = 84³).

It can be divided in two parts, 163 and 657, that added together give a triangular number (820 = T₄₀).

The spelling of 163657 in words is "one hundred sixty-three thousand, six hundred fifty-seven".