9957 has 4 divisors (see below), whose sum is σ = 13280. Its totient is φ = 6636.

The previous prime is 9949. The next prime is 9967. The reversal of 9957 is 7599.

It is a happy number.

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 not a de Polignac number, because 9957 - 2³ = 9949 is a prime.

It is a D-number.

It is a Duffinian number.

9957 is a lucky number.

It is a plaindrome in base 8 and base 13.

It is a nialpdrome in base 11.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 9957.

It is not an unprimeable number, because it can be changed into a prime (9907) 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, 1657 + ... + 1662.

It is an arithmetic number, because the mean of its divisors is an integer number (3320).

2⁹⁹⁵⁷ is an apocalyptic number.

It is an amenable number.

9957 is a deficient number, since it is larger than the sum of its proper divisors (3323).

9957 is a wasteful number, since it uses less digits than its factorization.

9957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3322.

The product of its digits is 2835, while the sum is 30.

The square root of 9957 is about 99.7847683767. The cubic root of 9957 is about 21.5134223021.

The spelling of 9957 in words is "nine thousand, nine hundred fifty-seven".