7861391 has 2 divisors, whose sum is σ = 7861392. Its totient is φ = 7861390.

The previous prime is 7861367. The next prime is 7861393. The reversal of 7861391 is 1931687.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7861391 is a prime.

Together with 7861393, 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 (7861393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3930695 + 3930696.

It is an arithmetic number, because the mean of its divisors is an integer number (3930696).

Almost surely, 2^7861391 is an apocalyptic number.

7861391 is a deficient number, since it is larger than the sum of its proper divisors (1).

7861391 is an equidigital number, since it uses as much as digits as its factorization.

7861391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 35.

The square root of 7861391 is about 2803.8172194350. The cubic root of 7861391 is about 198.8381890450.

The spelling of 7861391 in words is "seven million, eight hundred sixty-one thousand, three hundred ninety-one".