686397842 has 8 divisors (see below), whose sum is σ = 1108796556. Its totient is φ = 316798992.

The previous prime is 686397779. The next prime is 686397923. The reversal of 686397842 is 248793686.

It can be written as a sum of positive squares in 2 ways, for example, as 683770201 + 2627641 = 26149^2 + 1621^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×686397842² = 942283995004513928, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13199933 + ... + 13199984.

Almost surely, 2^686397842 is an apocalyptic number.

686397842 is a deficient number, since it is larger than the sum of its proper divisors (422398714).

686397842 is a wasteful number, since it uses less digits than its factorization.

686397842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26399932.

The product of its digits is 3483648, while the sum is 53.

The square root of 686397842 is about 26199.1954456621. The cubic root of 686397842 is about 882.1151950089.

The spelling of 686397842 in words is "six hundred eighty-six million, three hundred ninety-seven thousand, eight hundred forty-two".