684240637 has 2 divisors, whose sum is σ = 684240638. Its totient is φ = 684240636.

The previous prime is 684240589. The next prime is 684240707. The reversal of 684240637 is 736042486.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 636754756 + 47485881 = 25234^2 + 6891^2 .

It is a cyclic number.

It is not a de Polignac number, because 684240637 - 2²³ = 675852029 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 684240637.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684240937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342120318 + 342120319.

It is an arithmetic number, because the mean of its divisors is an integer number (342120319).

Almost surely, 2^684240637 is an apocalyptic number.

It is an amenable number.

684240637 is a deficient number, since it is larger than the sum of its proper divisors (1).

684240637 is an equidigital number, since it uses as much as digits as its factorization.

684240637 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 193536, while the sum is 40.

The square root of 684240637 is about 26157.9937495214. The cubic root of 684240637 is about 881.1901239804.

The spelling of 684240637 in words is "six hundred eighty-four million, two hundred forty thousand, six hundred thirty-seven".