12778989 has 16 divisors (see below), whose sum is σ = 17496000. Its totient is φ = 8293376.

The previous prime is 12778981. The next prime is 12778993. The reversal of 12778989 is 98987721.

It is a cyclic number.

It is not a de Polignac number, because 12778989 - 2³ = 12778981 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12778981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28237 + ... + 28685.

It is an arithmetic number, because the mean of its divisors is an integer number (1093500).

Almost surely, 2^12778989 is an apocalyptic number.

It is an amenable number.

12778989 is a deficient number, since it is larger than the sum of its proper divisors (4717011).

12778989 is a wasteful number, since it uses less digits than its factorization.

12778989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684.

The product of its digits is 508032, while the sum is 51.

The square root of 12778989 is about 3574.7711814884. The cubic root of 12778989 is about 233.7933561756.

Adding to 12778989 its sum of digits (51), we get a triangular number (12779040 = T₅₀₅₅).

The spelling of 12778989 in words is "twelve million, seven hundred seventy-eight thousand, nine hundred eighty-nine".