7878989 has 2 divisors, whose sum is σ = 7878990. Its totient is φ = 7878988.

The previous prime is 7878979. The next prime is 7879021. The reversal of 7878989 is 9898787.

7878989 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4656964 + 3222025 = 2158^2 + 1795^2 .

It is a cyclic number.

It is not a de Polignac number, because 7878989 - 2¹⁶ = 7813453 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7878979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3939494 + 3939495.

It is an arithmetic number, because the mean of its divisors is an integer number (3939495).

Almost surely, 2^7878989 is an apocalyptic number.

It is an amenable number.

7878989 is a deficient number, since it is larger than the sum of its proper divisors (1).

7878989 is an equidigital number, since it uses as much as digits as its factorization.

7878989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2032128, while the sum is 56.

The square root of 7878989 is about 2806.9536868285. The cubic root of 7878989 is about 198.9864472307.

The spelling of 7878989 in words is "seven million, eight hundred seventy-eight thousand, nine hundred eighty-nine".