12778815 has 32 divisors (see below), whose sum is σ = 24744960. Its totient is φ = 5497344.

The previous prime is 12778813. The next prime is 12778817. The reversal of 12778815 is 51887721.

It is an interprime number because it is at equal distance from previous prime (12778813) and next prime (12778817).

It is not a de Polignac number, because 12778815 - 2¹ = 12778813 is a prime.

It is a super-2 number, since 2×12778815² = 326596225608450, which contains 22 as substring.

It is a congruent number.

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

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1795 + ... + 5364.

It is an arithmetic number, because the mean of its divisors is an integer number (773280).

Almost surely, 2^12778815 is an apocalyptic number.

12778815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

12778815 is a deficient number, since it is larger than the sum of its proper divisors (11966145).

12778815 is a wasteful number, since it uses less digits than its factorization.

12778815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7191.

The product of its digits is 31360, while the sum is 39.

The square root of 12778815 is about 3574.7468441835. The cubic root of 12778815 is about 233.7922950528.

The spelling of 12778815 in words is "twelve million, seven hundred seventy-eight thousand, eight hundred fifteen".