691489398457 has 24 divisors (see below), whose sum is σ = 840656139848. Its totient is φ = 564587781120.

The previous prime is 691489398433. The next prime is 691489398539. The reversal of 691489398457 is 754893984196.

It can be written as a sum of positive squares in 4 ways, for example, as 125449847721 + 566039550736 = 354189^2 + 752356^2 .

It is not a de Polignac number, because 691489398457 - 2²⁷ = 691355180729 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 691489398457.

It is not an unprimeable number, because it can be changed into a prime (691489398427) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5882328 + ... + 5998729.

Almost surely, 2^691489398457 is an apocalyptic number.

It is an amenable number.

691489398457 is a deficient number, since it is larger than the sum of its proper divisors (149166741391).

691489398457 is a wasteful number, since it uses less digits than its factorization.

691489398457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11881129 (or 11881118 counting only the distinct ones).

The product of its digits is 470292480, while the sum is 73.

The spelling of 691489398457 in words is "six hundred ninety-one billion, four hundred eighty-nine million, three hundred ninety-eight thousand, four hundred fifty-seven".