689817987 has 6 divisors (see below), whose sum is σ = 996403772. Its totient is φ = 459878652.

The previous prime is 689817977. The next prime is 689817991. The reversal of 689817987 is 789718986.

It is not a de Polignac number, because 689817987 - 2⁶ = 689817923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (689817937) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 38323213 + ... + 38323230.

Almost surely, 2^689817987 is an apocalyptic number.

689817987 is a deficient number, since it is larger than the sum of its proper divisors (306585785).

689817987 is a wasteful number, since it uses less digits than its factorization.

689817987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76646449 (or 76646446 counting only the distinct ones).

The product of its digits is 12192768, while the sum is 63.

The square root of 689817987 is about 26264.3862863765. The cubic root of 689817987 is about 883.5778864676.

Subtracting 689817987 from its reverse (789718986), we obtain a palindrome (99900999).

The spelling of 689817987 in words is "six hundred eighty-nine million, eight hundred seventeen thousand, nine hundred eighty-seven".