11999555 has 4 divisors (see below), whose sum is σ = 14399472. Its totient is φ = 9599640.

The previous prime is 11999551. The next prime is 11999563. The reversal of 11999555 is 55599911.

It is a happy number.

11999555 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55599911 = 17 ⋅3270583.

It is not a de Polignac number, because 11999555 - 2² = 11999551 is a prime.

It is a Duffinian number.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (11999551) 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, 1199951 + ... + 1199960.

It is an arithmetic number, because the mean of its divisors is an integer number (3599868).

Almost surely, 2^11999555 is an apocalyptic number.

11999555 is a deficient number, since it is larger than the sum of its proper divisors (2399917).

11999555 is an equidigital number, since it uses as much as digits as its factorization.

11999555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2399916.

The product of its digits is 91125, while the sum is 44.

The square root of 11999555 is about 3464.0373843248. The cubic root of 11999555 is about 228.9400184877.

The spelling of 11999555 in words is "eleven million, nine hundred ninety-nine thousand, five hundred fifty-five".