688631549 has 4 divisors (see below), whose sum is σ = 688949760. Its totient is φ = 688313340.

The previous prime is 688631533. The next prime is 688631609. The reversal of 688631549 is 945136886.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 688631549 - 2⁴ = 688631533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 688631497 and 688631506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688651549) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155837 + ... + 160194.

It is an arithmetic number, because the mean of its divisors is an integer number (172237440).

Almost surely, 2^688631549 is an apocalyptic number.

It is an amenable number.

688631549 is a deficient number, since it is larger than the sum of its proper divisors (318211).

688631549 is a wasteful number, since it uses less digits than its factorization.

688631549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318210.

The product of its digits is 1244160, while the sum is 50.

The square root of 688631549 is about 26241.7901256755. The cubic root of 688631549 is about 883.0710320115.

The spelling of 688631549 in words is "six hundred eighty-eight million, six hundred thirty-one thousand, five hundred forty-nine".