686356081 has 2 divisors, whose sum is σ = 686356082. Its totient is φ = 686356080.

The previous prime is 686356063. The next prime is 686356091. The reversal of 686356081 is 180653686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 519429681 + 166926400 = 22791^2 + 12920^2 .

It is a cyclic number.

It is not a de Polignac number, because 686356081 - 2⁵ = 686356049 is a prime.

It is a super-2 number, since 2×686356081² = 942169339851357122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (686356061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343178040 + 343178041.

It is an arithmetic number, because the mean of its divisors is an integer number (343178041).

Almost surely, 2^686356081 is an apocalyptic number.

It is an amenable number.

686356081 is a deficient number, since it is larger than the sum of its proper divisors (1).

686356081 is an equidigital number, since it uses as much as digits as its factorization.

686356081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 207360, while the sum is 43.

The square root of 686356081 is about 26198.3984434163. The cubic root of 686356081 is about 882.0973051121.

The spelling of 686356081 in words is "six hundred eighty-six million, three hundred fifty-six thousand, eighty-one".