691363055506 has 4 divisors (see below), whose sum is σ = 1037044583262. Its totient is φ = 345681527752.

The previous prime is 691363055501. The next prime is 691363055521. The reversal of 691363055506 is 605550363196.

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

It can be written as a sum of positive squares in only one way, i.e., 687779955625 + 3583099881 = 829325^2 + 59859^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 691363055506.

It is not an unprimeable number, because it can be changed into a prime (691363055501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172840763875 + ... + 172840763878.

Almost surely, 2^691363055506 is an apocalyptic number.

691363055506 is a deficient number, since it is larger than the sum of its proper divisors (345681527756).

691363055506 is a wasteful number, since it uses less digits than its factorization.

691363055506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345681527755.

The product of its (nonzero) digits is 2187000, while the sum is 49.

The spelling of 691363055506 in words is "six hundred ninety-one billion, three hundred sixty-three million, fifty-five thousand, five hundred six".