253991 has 4 divisors (see below), whose sum is σ = 255000. Its totient is φ = 252984.

The previous prime is 253987. The next prime is 253993. The reversal of 253991 is 199352.

253991 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 brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 253991 - 2² = 253987 is a prime.

It is a super-2 number, since 2×253991² = 129022856162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (253993) 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, 245 + ... + 753.

It is an arithmetic number, because the mean of its divisors is an integer number (63750).

2²⁵³⁹⁹¹ is an apocalyptic number.

253991 is a deficient number, since it is larger than the sum of its proper divisors (1009).

253991 is an equidigital number, since it uses as much as digits as its factorization.

253991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008.

The product of its digits is 2430, while the sum is 29.

The square root of 253991 is about 503.9751978024. The cubic root of 253991 is about 63.3295073097.

The spelling of 253991 in words is "two hundred fifty-three thousand, nine hundred ninety-one".