12778819 has 4 divisors (see below), whose sum is σ = 12801544. Its totient is φ = 12756096.

The previous prime is 12778817. The next prime is 12778853. The reversal of 12778819 is 91887721.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91887721 = 59 ⋅1557419.

It is a cyclic number.

It is not a de Polignac number, because 12778819 - 2¹ = 12778817 is a prime.

It is a super-2 number, since 2×12778819² = 326596430069522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12778813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10497 + ... + 11650.

It is an arithmetic number, because the mean of its divisors is an integer number (3200386).

Almost surely, 2^12778819 is an apocalyptic number.

12778819 is a deficient number, since it is larger than the sum of its proper divisors (22725).

12778819 is an equidigital number, since it uses as much as digits as its factorization.

12778819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22724.

The product of its digits is 56448, while the sum is 43.

The square root of 12778819 is about 3574.7474036636. The cubic root of 12778819 is about 233.7923194466.

The spelling of 12778819 in words is "twelve million, seven hundred seventy-eight thousand, eight hundred nineteen".