11827991 has 4 divisors (see below), whose sum is σ = 13517712. Its totient is φ = 10138272.

The previous prime is 11827987. The next prime is 11827993. The reversal of 11827991 is 19972811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19972811 = 977 ⋅20443.

It is a cyclic number.

It is not a de Polignac number, because 11827991 - 2² = 11827987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11827993) 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, 844850 + ... + 844863.

It is an arithmetic number, because the mean of its divisors is an integer number (3379428).

Almost surely, 2^11827991 is an apocalyptic number.

11827991 is a deficient number, since it is larger than the sum of its proper divisors (1689721).

11827991 is an equidigital number, since it uses as much as digits as its factorization.

11827991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1689720.

The product of its digits is 9072, while the sum is 38.

The square root of 11827991 is about 3439.1846417429. The cubic root of 11827991 is about 227.8436845350.

The spelling of 11827991 in words is "eleven million, eight hundred twenty-seven thousand, nine hundred ninety-one".