11991859 has 4 divisors (see below), whose sum is σ = 13082040. Its totient is φ = 10901680.

The previous prime is 11991839. The next prime is 11991911. The reversal of 11991859 is 95819911.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 11991859 - 2⁷ = 11991731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11991839) 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, 545074 + ... + 545095.

It is an arithmetic number, because the mean of its divisors is an integer number (3270510).

Almost surely, 2^11991859 is an apocalyptic number.

11991859 is a deficient number, since it is larger than the sum of its proper divisors (1090181).

11991859 is a wasteful number, since it uses less digits than its factorization.

11991859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1090180.

The product of its digits is 29160, while the sum is 43.

The square root of 11991859 is about 3462.9263636410. The cubic root of 11991859 is about 228.8910639170.

The spelling of 11991859 in words is "eleven million, nine hundred ninety-one thousand, eight hundred fifty-nine".