691357967 has 2 divisors, whose sum is σ = 691357968. Its totient is φ = 691357966.

The previous prime is 691357889. The next prime is 691357969. The reversal of 691357967 is 769753196.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691357967 - 2¹⁴ = 691341583 is a prime.

It is a super-3 number, since 3×691357967³ (a number of 27 digits) contains 333 as substring.

Together with 691357969, 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 (691357969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345678983 + 345678984.

It is an arithmetic number, because the mean of its divisors is an integer number (345678984).

Almost surely, 2^691357967 is an apocalyptic number.

691357967 is a deficient number, since it is larger than the sum of its proper divisors (1).

691357967 is an equidigital number, since it uses as much as digits as its factorization.

691357967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2143260, while the sum is 53.

The square root of 691357967 is about 26293.6868278300. The cubic root of 691357967 is about 884.2349104927.

The spelling of 691357967 in words is "six hundred ninety-one million, three hundred fifty-seven thousand, nine hundred sixty-seven".