695821391 has 2 divisors, whose sum is σ = 695821392. Its totient is φ = 695821390.

The previous prime is 695821367. The next prime is 695821393. The reversal of 695821391 is 193128596.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 695821391 - 2¹⁸ = 695559247 is a prime.

Together with 695821393, 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 (695821393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 347910695 + 347910696.

It is an arithmetic number, because the mean of its divisors is an integer number (347910696).

Almost surely, 2^695821391 is an apocalyptic number.

695821391 is a deficient number, since it is larger than the sum of its proper divisors (1).

695821391 is an equidigital number, since it uses as much as digits as its factorization.

695821391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 116640, while the sum is 44.

The square root of 695821391 is about 26378.4266210098. The cubic root of 695821391 is about 886.1337108624.

The spelling of 695821391 in words is "six hundred ninety-five million, eight hundred twenty-one thousand, three hundred ninety-one".