870391 has 2 divisors, whose sum is σ = 870392. Its totient is φ = 870390.

The previous prime is 870367. The next prime is 870403. The reversal of 870391 is 193078.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 870391 - 2⁹ = 869879 is a prime.

870391 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (870301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 435195 + 435196.

It is an arithmetic number, because the mean of its divisors is an integer number (435196).

2⁸⁷⁰³⁹¹ is an apocalyptic number.

870391 is a deficient number, since it is larger than the sum of its proper divisors (1).

870391 is an equidigital number, since it uses as much as digits as its factorization.

870391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 870391 is about 932.9474797651. The cubic root of 870391 is about 95.4783262676.

The spelling of 870391 in words is "eight hundred seventy thousand, three hundred ninety-one".