11991949 has 4 divisors (see below), whose sum is σ = 12126780. Its totient is φ = 11857120.

The previous prime is 11991943. The next prime is 11991977. The reversal of 11991949 is 94919911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94919911 = 37 ⋅2565403.

It can be written as a sum of positive squares in 2 ways, for example, as 722500 + 11269449 = 850^2 + 3357^2 .

It is a cyclic number.

It is not a de Polignac number, because 11991949 - 2¹⁹ = 11467661 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 (11991943) 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, 67282 + ... + 67459.

It is an arithmetic number, because the mean of its divisors is an integer number (3031695).

Almost surely, 2^11991949 is an apocalyptic number.

It is an amenable number.

11991949 is a deficient number, since it is larger than the sum of its proper divisors (134831).

11991949 is an equidigital number, since it uses as much as digits as its factorization.

11991949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134830.

The product of its digits is 26244, while the sum is 43.

The square root of 11991949 is about 3462.9393584064. The cubic root of 11991949 is about 228.8916365317.

The spelling of 11991949 in words is "eleven million, nine hundred ninety-one thousand, nine hundred forty-nine".