12345667778 has 16 divisors (see below), whose sum is σ = 19186200000. Its totient is φ = 5950915152.

The previous prime is 12345667771. The next prime is 12345667783. The reversal of 12345667778 is 87776654321.

It is a happy number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (12345667771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 123278 + ... + 199721.

It is an arithmetic number, because the mean of its divisors is an integer number (1199137500).

Almost surely, 2^12345667778 is an apocalyptic number.

12345667778 is a deficient number, since it is larger than the sum of its proper divisors (6840532222).

12345667778 is a wasteful number, since it uses less digits than its factorization.

12345667778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323689.

The product of its digits is 11854080, while the sum is 56.

The spelling of 12345667778 in words is "twelve billion, three hundred forty-five million, six hundred sixty-seven thousand, seven hundred seventy-eight".