7878123889 has 2 divisors, whose sum is σ = 7878123890. Its totient is φ = 7878123888.

The previous prime is 7878123823. The next prime is 7878123907. The reversal of 7878123889 is 9883218787.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5964936289 + 1913187600 = 77233^2 + 43740^2 .

It is a cyclic number.

It is not a de Polignac number, because 7878123889 - 2¹⁷ = 7877992817 is a prime.

It is not a weakly prime, because it can be changed into another prime (7878123809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3939061944 + 3939061945.

It is an arithmetic number, because the mean of its divisors is an integer number (3939061945).

Almost surely, 2^7878123889 is an apocalyptic number.

It is an amenable number.

7878123889 is a deficient number, since it is larger than the sum of its proper divisors (1).

7878123889 is an equidigital number, since it uses as much as digits as its factorization.

7878123889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10838016, while the sum is 61.

The square root of 7878123889 is about 88758.7961218492. The cubic root of 7878123889 is about 1989.7916407692.

The spelling of 7878123889 in words is "seven billion, eight hundred seventy-eight million, one hundred twenty-three thousand, eight hundred eighty-nine".