686999407 has 2 divisors, whose sum is σ = 686999408. Its totient is φ = 686999406.

The previous prime is 686999399. The next prime is 686999413. The reversal of 686999407 is 704999686.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 686999407 - 2³ = 686999399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686999447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343499703 + 343499704.

It is an arithmetic number, because the mean of its divisors is an integer number (343499704).

Almost surely, 2^686999407 is an apocalyptic number.

686999407 is a deficient number, since it is larger than the sum of its proper divisors (1).

686999407 is an equidigital number, since it uses as much as digits as its factorization.

686999407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5878656, while the sum is 58.

The square root of 686999407 is about 26210.6735319793. The cubic root of 686999407 is about 882.3728175558.

It can be divided in two parts, 6869 and 99407, that added together give a square (106276 = 326²).

The spelling of 686999407 in words is "six hundred eighty-six million, nine hundred ninety-nine thousand, four hundred seven".