261993 has 8 divisors (see below), whose sum is σ = 364608. Its totient is φ = 167024.

The previous prime is 261983. The next prime is 262007. The reversal of 261993 is 399162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261993 - 2⁴ = 261977 is a prime.

It is a Curzon number.

It is a nialpdrome in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 261993.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1830 + ... + 1967.

It is an arithmetic number, because the mean of its divisors is an integer number (45576).

2²⁶¹⁹⁹³ is an apocalyptic number.

261993 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

261993 is a deficient number, since it is larger than the sum of its proper divisors (102615).

261993 is a wasteful number, since it uses less digits than its factorization.

261993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3823.

The product of its digits is 2916, while the sum is 30.

The square root of 261993 is about 511.8525178213. The cubic root of 261993 is about 63.9877092283.

The spelling of 261993 in words is "two hundred sixty-one thousand, nine hundred ninety-three".