687751549 has 2 divisors, whose sum is σ = 687751550. Its totient is φ = 687751548.

The previous prime is 687751499. The next prime is 687751573. The reversal of 687751549 is 945157786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 538472025 + 149279524 = 23205^2 + 12218^2 .

It is a cyclic number.

It is not a de Polignac number, because 687751549 - 2¹⁵ = 687718781 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 687751496 and 687751505.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687751579) 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, 343875774 + 343875775.

It is an arithmetic number, because the mean of its divisors is an integer number (343875775).

Almost surely, 2^687751549 is an apocalyptic number.

It is an amenable number.

687751549 is a deficient number, since it is larger than the sum of its proper divisors (1).

687751549 is an equidigital number, since it uses as much as digits as its factorization.

687751549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2116800, while the sum is 52.

The square root of 687751549 is about 26225.0176167720. The cubic root of 687751549 is about 882.6947138079.

The spelling of 687751549 in words is "six hundred eighty-seven million, seven hundred fifty-one thousand, five hundred forty-nine".