686554391 has 2 divisors, whose sum is σ = 686554392. Its totient is φ = 686554390.

The previous prime is 686554387. The next prime is 686554423. The reversal of 686554391 is 193455686.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 686554391 - 2² = 686554387 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686854391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343277195 + 343277196.

It is an arithmetic number, because the mean of its divisors is an integer number (343277196).

Almost surely, 2^686554391 is an apocalyptic number.

686554391 is a deficient number, since it is larger than the sum of its proper divisors (1).

686554391 is an equidigital number, since it uses as much as digits as its factorization.

686554391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 777600, while the sum is 47.

The square root of 686554391 is about 26202.1829434114. The cubic root of 686554391 is about 882.1822522101.

The spelling of 686554391 in words is "six hundred eighty-six million, five hundred fifty-four thousand, three hundred ninety-one".