691689811451 has 4 divisors (see below), whose sum is σ = 695511302304. Its totient is φ = 687868320600.

The previous prime is 691689811433. The next prime is 691689811459. The reversal of 691689811451 is 154118986196.

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 691689811451 - 2¹⁸ = 691689549307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691689811459) 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, 1910745155 + ... + 1910745516.

It is an arithmetic number, because the mean of its divisors is an integer number (173877825576).

Almost surely, 2^691689811451 is an apocalyptic number.

691689811451 is a deficient number, since it is larger than the sum of its proper divisors (3821490853).

691689811451 is a wasteful number, since it uses less digits than its factorization.

691689811451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3821490852.

The product of its digits is 3732480, while the sum is 59.

The spelling of 691689811451 in words is "six hundred ninety-one billion, six hundred eighty-nine million, eight hundred eleven thousand, four hundred fifty-one".