1139991 has 4 divisors (see below), whose sum is σ = 1519992. Its totient is φ = 759992.

The previous prime is 1139989. The next prime is 1139993. The reversal of 1139991 is 1999311.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1999311 = 3 ⋅666437.

It is an interprime number because it is at equal distance from previous prime (1139989) and next prime (1139993).

It is a cyclic number.

It is not a de Polignac number, because 1139991 - 2¹ = 1139989 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1139993) 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, 189996 + ... + 190001.

It is an arithmetic number, because the mean of its divisors is an integer number (379998).

2^1139991 is an apocalyptic number.

1139991 is a deficient number, since it is larger than the sum of its proper divisors (380001).

1139991 is an equidigital number, since it uses as much as digits as its factorization.

1139991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380000.

The product of its digits is 2187, while the sum is 33.

The square root of 1139991 is about 1067.7036105587. The cubic root of 1139991 is about 104.4641177752.

The spelling of 1139991 in words is "one million, one hundred thirty-nine thousand, nine hundred ninety-one".