687631913 has 2 divisors, whose sum is σ = 687631914. Its totient is φ = 687631912.

The previous prime is 687631883. The next prime is 687631957. The reversal of 687631913 is 319136786.

It is an a-pointer prime, because the next prime (687631957) can be obtained adding 687631913 to its sum of digits (44).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 682672384 + 4959529 = 26128^2 + 2227^2 .

It is a cyclic number.

It is not a de Polignac number, because 687631913 - 2¹⁸ = 687369769 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (687631613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343815956 + 343815957.

It is an arithmetic number, because the mean of its divisors is an integer number (343815957).

Almost surely, 2^687631913 is an apocalyptic number.

It is an amenable number.

687631913 is a deficient number, since it is larger than the sum of its proper divisors (1).

687631913 is an equidigital number, since it uses as much as digits as its factorization.

687631913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 44.

The square root of 687631913 is about 26222.7365658125. The cubic root of 687631913 is about 882.6435285658.

The spelling of 687631913 in words is "six hundred eighty-seven million, six hundred thirty-one thousand, nine hundred thirteen".