687631999 has 2 divisors, whose sum is σ = 687632000. Its totient is φ = 687631998.

The previous prime is 687631981. The next prime is 687632003. The reversal of 687631999 is 999136786.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 687631999 - 2¹¹ = 687629951 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687631979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343815999 + 343816000.

It is an arithmetic number, because the mean of its divisors is an integer number (343816000).

Almost surely, 2^687631999 is an apocalyptic number.

687631999 is a deficient number, since it is larger than the sum of its proper divisors (1).

687631999 is an equidigital number, since it uses as much as digits as its factorization.

687631999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4408992, while the sum is 58.

The square root of 687631999 is about 26222.7382056108. The cubic root of 687631999 is about 882.6435653623.

The spelling of 687631999 in words is "six hundred eighty-seven million, six hundred thirty-one thousand, nine hundred ninety-nine".