691565286491 has 4 divisors (see below), whose sum is σ = 694061912352. Its totient is φ = 689068660632.

The previous prime is 691565286469. The next prime is 691565286527. The reversal of 691565286491 is 194682565196.

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

It is a cyclic number.

It is not a de Polignac number, because 691565286491 - 2⁶ = 691565286427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691565286991) 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, 1248312515 + ... + 1248313068.

It is an arithmetic number, because the mean of its divisors is an integer number (173515478088).

Almost surely, 2^691565286491 is an apocalyptic number.

691565286491 is a deficient number, since it is larger than the sum of its proper divisors (2496625861).

691565286491 is a wasteful number, since it uses less digits than its factorization.

691565286491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2496625860.

The product of its digits is 27993600, while the sum is 62.

The spelling of 691565286491 in words is "six hundred ninety-one billion, five hundred sixty-five million, two hundred eighty-six thousand, four hundred ninety-one".