878578991 has 2 divisors, whose sum is σ = 878578992. Its totient is φ = 878578990.

The previous prime is 878578969. The next prime is 878578993. The reversal of 878578991 is 199875878.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-878578991 is a prime.

Together with 878578993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (878578993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 439289495 + 439289496.

It is an arithmetic number, because the mean of its divisors is an integer number (439289496).

Almost surely, 2^878578991 is an apocalyptic number.

878578991 is a deficient number, since it is larger than the sum of its proper divisors (1).

878578991 is an equidigital number, since it uses as much as digits as its factorization.

878578991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10160640, while the sum is 62.

The square root of 878578991 is about 29640.8331698014. The cubic root of 878578991 is about 957.7678866503.

The spelling of 878578991 in words is "eight hundred seventy-eight million, five hundred seventy-eight thousand, nine hundred ninety-one".