686390197 has 2 divisors, whose sum is σ = 686390198. Its totient is φ = 686390196.

The previous prime is 686390179. The next prime is 686390261. The reversal of 686390197 is 791093686.

Together with previous prime (686390179) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 683874801 + 2515396 = 26151^2 + 1586^2 .

It is a cyclic number.

It is not a de Polignac number, because 686390197 - 2¹⁵ = 686357429 is a prime.

It is a super-2 number, since 2×686390197² = 942263005075397618, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 686390197.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686390167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343195098 + 343195099.

It is an arithmetic number, because the mean of its divisors is an integer number (343195099).

Almost surely, 2^686390197 is an apocalyptic number.

It is an amenable number.

686390197 is a deficient number, since it is larger than the sum of its proper divisors (1).

686390197 is an equidigital number, since it uses as much as digits as its factorization.

686390197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 489888, while the sum is 49.

The square root of 686390197 is about 26199.0495438289. The cubic root of 686390197 is about 882.1119200396. Note that the first 3 decimals are identical.

The spelling of 686390197 in words is "six hundred eighty-six million, three hundred ninety thousand, one hundred ninety-seven".