687721499 has 2 divisors, whose sum is σ = 687721500. Its totient is φ = 687721498.

The previous prime is 687721487. The next prime is 687721547. The reversal of 687721499 is 994127786.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 687721499 - 2²⁰ = 686672923 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 687721499.

It is not a weakly prime, because it can be changed into another prime (687721429) 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, 343860749 + 343860750.

It is an arithmetic number, because the mean of its divisors is an integer number (343860750).

Almost surely, 2^687721499 is an apocalyptic number.

687721499 is a deficient number, since it is larger than the sum of its proper divisors (1).

687721499 is an equidigital number, since it uses as much as digits as its factorization.

687721499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1524096, while the sum is 53.

The square root of 687721499 is about 26224.4446843017. Note that the first 3 decimals coincide. The cubic root of 687721499 is about 882.6818577300.

The spelling of 687721499 in words is "six hundred eighty-seven million, seven hundred twenty-one thousand, four hundred ninety-nine".