685721734 has 4 divisors (see below), whose sum is σ = 1028582604. Its totient is φ = 342860866.

The previous prime is 685721717. The next prime is 685721783. The reversal of 685721734 is 437127586.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171430432 + ... + 171430435.

It is an arithmetic number, because the mean of its divisors is an integer number (257145651).

Almost surely, 2^685721734 is an apocalyptic number.

685721734 is a deficient number, since it is larger than the sum of its proper divisors (342860870).

685721734 is a wasteful number, since it uses less digits than its factorization.

685721734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342860869.

The product of its digits is 282240, while the sum is 43.

The square root of 685721734 is about 26186.2890459874. The cubic root of 685721734 is about 881.8254694142.

The spelling of 685721734 in words is "six hundred eighty-five million, seven hundred twenty-one thousand, seven hundred thirty-four".