687252409 has 2 divisors, whose sum is σ = 687252410. Its totient is φ = 687252408.

The previous prime is 687252407. The next prime is 687252437. The reversal of 687252409 is 904252786.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 612810025 + 74442384 = 24755^2 + 8628^2 .

It is a cyclic number.

It is not a de Polignac number, because 687252409 - 2¹ = 687252407 is a prime.

Together with 687252407, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (687252403) 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, 343626204 + 343626205.

It is an arithmetic number, because the mean of its divisors is an integer number (343626205).

Almost surely, 2^687252409 is an apocalyptic number.

It is an amenable number.

687252409 is a deficient number, since it is larger than the sum of its proper divisors (1).

687252409 is an equidigital number, since it uses as much as digits as its factorization.

687252409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 43.

The square root of 687252409 is about 26215.4994039786. The cubic root of 687252409 is about 882.4811217195.

The spelling of 687252409 in words is "six hundred eighty-seven million, two hundred fifty-two thousand, four hundred nine".