687631723 has 2 divisors, whose sum is σ = 687631724. Its totient is φ = 687631722.

The previous prime is 687631649. The next prime is 687631727. The reversal of 687631723 is 327136786.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 687631723 - 2⁹ = 687631211 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 687631723.

It is not a weakly prime, because it can be changed into another prime (687631727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343815861 + 343815862.

It is an arithmetic number, because the mean of its divisors is an integer number (343815862).

Almost surely, 2^687631723 is an apocalyptic number.

687631723 is a deficient number, since it is larger than the sum of its proper divisors (1).

687631723 is an equidigital number, since it uses as much as digits as its factorization.

687631723 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 43.

The square root of 687631723 is about 26222.7329430020. The cubic root of 687631723 is about 882.6434472712.

The spelling of 687631723 in words is "six hundred eighty-seven million, six hundred thirty-one thousand, seven hundred twenty-three".