687388817 has 2 divisors, whose sum is σ = 687388818. Its totient is φ = 687388816.

The previous prime is 687388813. The next prime is 687388847. The reversal of 687388817 is 718883786.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 607178881 + 80209936 = 24641^2 + 8956^2 .

It is a cyclic number.

It is not a de Polignac number, because 687388817 - 2² = 687388813 is a prime.

It is not a weakly prime, because it can be changed into another prime (687388811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343694408 + 343694409.

It is an arithmetic number, because the mean of its divisors is an integer number (343694409).

Almost surely, 2^687388817 is an apocalyptic number.

It is an amenable number.

687388817 is a deficient number, since it is larger than the sum of its proper divisors (1).

687388817 is an equidigital number, since it uses as much as digits as its factorization.

687388817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3612672, while the sum is 56.

The square root of 687388817 is about 26218.1009419065. The cubic root of 687388817 is about 882.5395037248.

The spelling of 687388817 in words is "six hundred eighty-seven million, three hundred eighty-eight thousand, eight hundred seventeen".