1233991 has 4 divisors (see below), whose sum is σ = 1346184. Its totient is φ = 1121800.

The previous prime is 1233983. The next prime is 1234001. The reversal of 1233991 is 1993321.

1233991 = 451² + 452² + ... + 456².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1993321 = 11 ⋅181211.

It is a cyclic number.

It is not a de Polignac number, because 1233991 - 2³ = 1233983 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1234991) 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, 56080 + ... + 56101.

It is an arithmetic number, because the mean of its divisors is an integer number (336546).

2^1233991 is an apocalyptic number.

1233991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1233991 is a deficient number, since it is larger than the sum of its proper divisors (112193).

1233991 is a wasteful number, since it uses less digits than its factorization.

1233991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112192.

The product of its digits is 1458, while the sum is 28.

The square root of 1233991 is about 1110.8514752207. The cubic root of 1233991 is about 107.2598859255.

It can be divided in two parts, 123 and 3991, that added together give a palindrome (4114).

The spelling of 1233991 in words is "one million, two hundred thirty-three thousand, nine hundred ninety-one".