686910649 has 2 divisors, whose sum is σ = 686910650. Its totient is φ = 686910648.

The previous prime is 686910643. The next prime is 686910671. The reversal of 686910649 is 946019686.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 488100649 + 198810000 = 22093^2 + 14100^2 .

It is a cyclic number.

It is not a de Polignac number, because 686910649 - 2²⁹ = 150039737 is a prime.

It is not a weakly prime, because it can be changed into another prime (686910643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343455324 + 343455325.

It is an arithmetic number, because the mean of its divisors is an integer number (343455325).

Almost surely, 2^686910649 is an apocalyptic number.

It is an amenable number.

686910649 is a deficient number, since it is larger than the sum of its proper divisors (1).

686910649 is an equidigital number, since it uses as much as digits as its factorization.

686910649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 686910649 is about 26208.9803120991. The cubic root of 686910649 is about 882.3348160579.

The spelling of 686910649 in words is "six hundred eighty-six million, nine hundred ten thousand, six hundred forty-nine".