691765008056641 has 4 divisors (see below), whose sum is σ = 691860701106900. Its totient is φ = 691669315006384.

The previous prime is 691765008056579. The next prime is 691765008056669. The reversal of 691765008056641 is 146650800567196.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 623089462297600 + 68675545759041 = 24961760^2 + 8287071^2 .

It is a cyclic number.

It is not a de Polignac number, because 691765008056641 - 2¹⁷ = 691765007925569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691765008056741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47846514286 + ... + 47846528743.

It is an arithmetic number, because the mean of its divisors is an integer number (172965175276725).

Almost surely, 2^{691765008056641} is an apocalyptic number.

It is an amenable number.

691765008056641 is a deficient number, since it is larger than the sum of its proper divisors (95693050259).

691765008056641 is an equidigital number, since it uses as much as digits as its factorization.

691765008056641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95693050258.

The product of its (nonzero) digits is 65318400, while the sum is 64.

The spelling of 691765008056641 in words is "six hundred ninety-one trillion, seven hundred sixty-five billion, eight million, fifty-six thousand, six hundred forty-one".