19957 has 4 divisors (see below), whose sum is σ = 22816. Its totient is φ = 17100.

The previous prime is 19949. The next prime is 19961. The reversal of 19957 is 75991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19957 - 2³ = 19949 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 (19927) 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, 1419 + ... + 1432.

It is an arithmetic number, because the mean of its divisors is an integer number (5704).

2¹⁹⁹⁵⁷ is an apocalyptic number.

It is an amenable number.

19957 is a deficient number, since it is larger than the sum of its proper divisors (2859).

19957 is an equidigital number, since it uses as much as digits as its factorization.

19957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2858.

The product of its digits is 2835, while the sum is 31.

The square root of 19957 is about 141.2692464764. The cubic root of 19957 is about 27.1247088815.

It can be divided in two parts, 1995 and 7, that added together give a palindrome (2002).

The spelling of 19957 in words is "nineteen thousand, nine hundred fifty-seven".