687139812773 has 4 divisors (see below), whose sum is σ = 687142962528. Its totient is φ = 687136663020.

The previous prime is 687139812739. The next prime is 687139812781. The reversal of 687139812773 is 377218931786.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687139812773 is a prime.

It is a super-2 number, since 2×687139812773² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687139892773) 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, 1221161 + ... + 1692782.

It is an arithmetic number, because the mean of its divisors is an integer number (171785740632).

Almost surely, 2^687139812773 is an apocalyptic number.

It is an amenable number.

687139812773 is a deficient number, since it is larger than the sum of its proper divisors (3149755).

687139812773 is a wasteful number, since it uses less digits than its factorization.

687139812773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3149754.

The product of its digits is 21337344, while the sum is 62.

The spelling of 687139812773 in words is "six hundred eighty-seven billion, one hundred thirty-nine million, eight hundred twelve thousand, seven hundred seventy-three".