878134391 has 2 divisors, whose sum is σ = 878134392. Its totient is φ = 878134390.

The previous prime is 878134373. The next prime is 878134393. The reversal of 878134391 is 193431878.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 878134391 - 2²² = 873940087 is a prime.

It is a super-2 number, since 2×878134391² = 1542240017313881762, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 878134393, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_44948654 and since 878134391 and 44948654 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (878134393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 439067195 + 439067196.

It is an arithmetic number, because the mean of its divisors is an integer number (439067196).

Almost surely, 2^878134391 is an apocalyptic number.

878134391 is a deficient number, since it is larger than the sum of its proper divisors (1).

878134391 is an equidigital number, since it uses as much as digits as its factorization.

878134391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 44.

The square root of 878134391 is about 29633.3324315710. The cubic root of 878134391 is about 957.6063016911.

The spelling of 878134391 in words is "eight hundred seventy-eight million, one hundred thirty-four thousand, three hundred ninety-one".