691155643 has 2 divisors, whose sum is σ = 691155644. Its totient is φ = 691155642.

The previous prime is 691155623. The next prime is 691155653. The reversal of 691155643 is 346551196.

It is a happy number.

691155643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691155643 - 2⁹ = 691155131 is a prime.

It is a super-2 number, since 2×691155643² = 955392245701486898, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 691155596 and 691155605.

It is not a weakly prime, because it can be changed into another prime (691155613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345577821 + 345577822.

It is an arithmetic number, because the mean of its divisors is an integer number (345577822).

Almost surely, 2^691155643 is an apocalyptic number.

691155643 is a deficient number, since it is larger than the sum of its proper divisors (1).

691155643 is an equidigital number, since it uses as much as digits as its factorization.

691155643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 97200, while the sum is 40.

The square root of 691155643 is about 26289.8391588842. The cubic root of 691155643 is about 884.1486457754.

The spelling of 691155643 in words is "six hundred ninety-one million, one hundred fifty-five thousand, six hundred forty-three".