7864391 has 2 divisors, whose sum is σ = 7864392. Its totient is φ = 7864390.

The previous prime is 7864379. The next prime is 7864397. The reversal of 7864391 is 1934687.

It is a strong prime.

It is an emirp because it is prime and its reverse (1934687) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7864391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7864397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3932195 + 3932196.

It is an arithmetic number, because the mean of its divisors is an integer number (3932196).

Almost surely, 2^7864391 is an apocalyptic number.

7864391 is a deficient number, since it is larger than the sum of its proper divisors (1).

7864391 is an equidigital number, since it uses as much as digits as its factorization.

7864391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 38.

The square root of 7864391 is about 2804.3521533502. The cubic root of 7864391 is about 198.8634788317.

The spelling of 7864391 in words is "seven million, eight hundred sixty-four thousand, three hundred ninety-one".