686686397 has 2 divisors, whose sum is σ = 686686398. Its totient is φ = 686686396.

The previous prime is 686686387. The next prime is 686686453. The reversal of 686686397 is 793686686.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 432889636 + 253796761 = 20806^2 + 15931^2 .

It is a cyclic number.

It is not a de Polignac number, because 686686397 - 2¹² = 686682301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686686387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343343198 + 343343199.

It is an arithmetic number, because the mean of its divisors is an integer number (343343199).

Almost surely, 2^686686397 is an apocalyptic number.

It is an amenable number.

686686397 is a deficient number, since it is larger than the sum of its proper divisors (1).

686686397 is an equidigital number, since it uses as much as digits as its factorization.

686686397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15676416, while the sum is 59.

The square root of 686686397 is about 26204.7018109346. The cubic root of 686686397 is about 882.2387885841.

The spelling of 686686397 in words is "six hundred eighty-six million, six hundred eighty-six thousand, three hundred ninety-seven".