687478331 has 2 divisors, whose sum is σ = 687478332. Its totient is φ = 687478330.

The previous prime is 687478313. The next prime is 687478339. The reversal of 687478331 is 133874786.

Together with previous prime (687478313) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 687478331 - 2²² = 683284027 is a prime.

It is a super-2 number, since 2×687478331² = 945252911189091122, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (687478339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343739165 + 343739166.

It is an arithmetic number, because the mean of its divisors is an integer number (343739166).

Almost surely, 2^687478331 is an apocalyptic number.

687478331 is a deficient number, since it is larger than the sum of its proper divisors (1).

687478331 is an equidigital number, since it uses as much as digits as its factorization.

687478331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 677376, while the sum is 47.

The square root of 687478331 is about 26219.8079893809. The cubic root of 687478331 is about 882.5778111137.

The spelling of 687478331 in words is "six hundred eighty-seven million, four hundred seventy-eight thousand, three hundred thirty-one".