2157 has 4 divisors (see below), whose sum is σ = 2880.
Its totient is φ = 1436.
The previous prime is 2153. The next prime is 2161. The reversal of 2157 is 7512.
It is a happy number.
2157 is nontrivially palindromic in base 13.
2157 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
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 an interprime number because it is at equal distance from previous prime (2153) and next prime (2161).
It is a cyclic number.
It is not a de Polignac number, because 2157 - 22 = 2153 is a prime.
It is a D-number.
2157 is an undulating number in base 13.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (2153) 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, 357 + ... + 362.
It is an arithmetic number, because the mean of its divisors is an integer number (720).
22157 is an apocalyptic number.
It is an amenable number.
2157 is a deficient number, since it is larger than the sum of its proper divisors (723).
2157 is an equidigital number, since it uses as much as digits as its factorization.
2157 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 722.
The product of its digits is 70, while the sum is 15.
The square root of 2157 is about 46.4435140789.
The cubic root of 2157 is about 12.9206208266.
Adding to 2157 its reverse (7512), we get a palindrome (9669).
It can be divided in two parts, 215 and 7, that added together give a palindrome (222).
The spelling of 2157 in words is "two thousand, one hundred fifty-seven".