688994009 has 16 divisors (see below), whose sum is σ = 769063680. Its totient is φ = 611880960.

The previous prime is 688993999. The next prime is 688994063. The reversal of 688994009 is 900499886.

It is a cyclic number.

It is not a de Polignac number, because 688994009 - 2⁴ = 688993993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (688994069) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 396707 + ... + 398439.

It is an arithmetic number, because the mean of its divisors is an integer number (48066480).

Almost surely, 2^688994009 is an apocalyptic number.

It is an amenable number.

688994009 is a deficient number, since it is larger than the sum of its proper divisors (80069671).

688994009 is a wasteful number, since it uses less digits than its factorization.

688994009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2560.

The product of its (nonzero) digits is 1119744, while the sum is 53.

The square root of 688994009 is about 26248.6953771040. The cubic root of 688994009 is about 883.2259391292.

The spelling of 688994009 in words is "six hundred eighty-eight million, nine hundred ninety-four thousand, nine".