686743690 has 12 divisors (see below), whose sum is σ = 1236287826. Its totient is φ = 274664328.

The previous prime is 686743667. The next prime is 686743691. The reversal of 686743690 is 96347686.

It can be written as a sum of positive squares in only one way, i.e., 618069321 + 68674369 = 24861^2 + 8287^2 .

It is a super-2 number, since 2×686743690² = 943233791509632200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (686743691) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 78727 + ... + 87013.

Almost surely, 2^686743690 is an apocalyptic number.

686743690 is a deficient number, since it is larger than the sum of its proper divisors (549544136).

686743690 is an frugal number, since it uses more digits than its factorization.

686743690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16581 (or 8294 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 49.

The square root of 686743690 is about 26205.7949698154. The cubic root of 686743690 is about 882.2633241418.

The spelling of 686743690 in words is "six hundred eighty-six million, seven hundred forty-three thousand, six hundred ninety".