12778640 has 80 divisors (see below), whose sum is σ = 35771520. Its totient is φ = 4147200.

The previous prime is 12778637. The next prime is 12778643. The reversal of 12778640 is 4687721.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (12778637) and next prime (12778643).

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 12778640.

It is not an unprimeable number, because it can be changed into a prime (12778643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10040 + ... + 11240.

It is an arithmetic number, because the mean of its divisors is an integer number (447144).

Almost surely, 2^12778640 is an apocalyptic number.

12778640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12778640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17885760).

12778640 is an abundant number, since it is smaller than the sum of its proper divisors (22992880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12778640 is a wasteful number, since it uses less digits than its factorization.

12778640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1240 (or 1234 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 12778640 is about 3574.7223668419. The cubic root of 12778640 is about 233.7912278219.

The spelling of 12778640 in words is "twelve million, seven hundred seventy-eight thousand, six hundred forty".