691744387 has 2 divisors, whose sum is σ = 691744388. Its totient is φ = 691744386.

The previous prime is 691744369. The next prime is 691744451. The reversal of 691744387 is 783447196.

691744387 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691744387 - 2²³ = 683355779 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 691744387.

It is not a weakly prime, because it can be changed into another prime (691744367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345872193 + 345872194.

It is an arithmetic number, because the mean of its divisors is an integer number (345872194).

Almost surely, 2^691744387 is an apocalyptic number.

691744387 is a deficient number, since it is larger than the sum of its proper divisors (1).

691744387 is an equidigital number, since it uses as much as digits as its factorization.

691744387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1016064, while the sum is 49.

The square root of 691744387 is about 26301.0339530597. The cubic root of 691744387 is about 884.3996213134.

The spelling of 691744387 in words is "six hundred ninety-one million, seven hundred forty-four thousand, three hundred eighty-seven".