11815997 has 4 divisors (see below), whose sum is σ = 12329760. Its totient is φ = 11302236.

The previous prime is 11815961. The next prime is 11816009. The reversal of 11815997 is 79951811.

11815997 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 a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 79951811 = 29 ⋅2756959.

It is a cyclic number.

It is not a de Polignac number, because 11815997 - 2¹⁰ = 11814973 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 (11815957) 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, 256847 + ... + 256892.

It is an arithmetic number, because the mean of its divisors is an integer number (3082440).

Almost surely, 2^11815997 is an apocalyptic number.

It is an amenable number.

11815997 is a deficient number, since it is larger than the sum of its proper divisors (513763).

11815997 is an equidigital number, since it uses as much as digits as its factorization.

11815997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513762.

The product of its digits is 22680, while the sum is 41.

The square root of 11815997 is about 3437.4404722118. The cubic root of 11815997 is about 227.7666446450.

The spelling of 11815997 in words is "eleven million, eight hundred fifteen thousand, nine hundred ninety-seven".