12399778 has 4 divisors (see below), whose sum is σ = 18599670. Its totient is φ = 6199888.

The previous prime is 12399769. The next prime is 12399787. The reversal of 12399778 is 87799321.

It is a happy number.

12399778 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: 87799321 = 179 ⋅490499.

It is an interprime number because it is at equal distance from previous prime (12399769) and next prime (12399787).

It can be written as a sum of positive squares in only one way, i.e., 12089529 + 310249 = 3477^2 + 557^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3099943 + ... + 3099946.

Almost surely, 2^12399778 is an apocalyptic number.

12399778 is a deficient number, since it is larger than the sum of its proper divisors (6199892).

12399778 is an equidigital number, since it uses as much as digits as its factorization.

12399778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6199891.

The product of its digits is 190512, while the sum is 46.

The square root of 12399778 is about 3521.3318503089. The cubic root of 12399778 is about 231.4575241573.

The spelling of 12399778 in words is "twelve million, three hundred ninety-nine thousand, seven hundred seventy-eight".