687757261 has 2 divisors, whose sum is σ = 687757262. Its totient is φ = 687757260.

The previous prime is 687757241. The next prime is 687757283. The reversal of 687757261 is 162757786.

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., 675012361 + 12744900 = 25981^2 + 3570^2 .

It is a cyclic number.

It is not a de Polignac number, because 687757261 - 2¹⁵ = 687724493 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687757241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343878630 + 343878631.

It is an arithmetic number, because the mean of its divisors is an integer number (343878631).

Almost surely, 2^687757261 is an apocalyptic number.

It is an amenable number.

687757261 is a deficient number, since it is larger than the sum of its proper divisors (1).

687757261 is an equidigital number, since it uses as much as digits as its factorization.

687757261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 987840, while the sum is 49.

The square root of 687757261 is about 26225.1265201905. The cubic root of 687757261 is about 882.6971574899.

The spelling of 687757261 in words is "six hundred eighty-seven million, seven hundred fifty-seven thousand, two hundred sixty-one".