691364777 has 2 divisors, whose sum is σ = 691364778. Its totient is φ = 691364776.

The previous prime is 691364749. The next prime is 691364819. The reversal of 691364777 is 777463196.

It is a happy number.

691364777 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 can be written as a sum of positive squares in only one way, i.e., 347039641 + 344325136 = 18629^2 + 18556^2 .

It is a cyclic number.

It is not a de Polignac number, because 691364777 - 2¹⁰ = 691363753 is a prime.

It is not a weakly prime, because it can be changed into another prime (691364747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345682388 + 345682389.

It is an arithmetic number, because the mean of its divisors is an integer number (345682389).

Almost surely, 2^691364777 is an apocalyptic number.

It is an amenable number.

691364777 is a deficient number, since it is larger than the sum of its proper divisors (1).

691364777 is an equidigital number, since it uses as much as digits as its factorization.

691364777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1333584, while the sum is 50.

The square root of 691364777 is about 26293.8163262772. The cubic root of 691364777 is about 884.2378137740.

The spelling of 691364777 in words is "six hundred ninety-one million, three hundred sixty-four thousand, seven hundred seventy-seven".