199957 has 4 divisors (see below), whose sum is σ = 204876. Its totient is φ = 195040.

The previous prime is 199933. The next prime is 199961. The reversal of 199957 is 759991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 759991 = 457 ⋅1663.

It can be written as a sum of positive squares in 2 ways, for example, as 28561 + 171396 = 169^2 + 414^2 .

It is a cyclic number.

It is not a de Polignac number, because 199957 - 2¹¹ = 197909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199967) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2398 + ... + 2479.

It is an arithmetic number, because the mean of its divisors is an integer number (51219).

2¹⁹⁹⁹⁵⁷ is an apocalyptic number.

It is an amenable number.

199957 is a deficient number, since it is larger than the sum of its proper divisors (4919).

199957 is an equidigital number, since it uses as much as digits as its factorization.

199957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4918.

The product of its digits is 25515, while the sum is 40.

The square root of 199957 is about 447.1655174541. The cubic root of 199957 is about 58.4761633718.

It can be divided in two parts, 19995 and 7, that added together give a palindrome (20002).

The spelling of 199957 in words is "one hundred ninety-nine thousand, nine hundred fifty-seven".