688380169 has 3 divisors (see below), whose sum is σ = 688406407. Its totient is φ = 688353932.

The previous prime is 688380157. The next prime is 688380239. The reversal of 688380169 is 961083886.

The square root of 688380169 is 26237.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 93605625 + 594774544 = 9675^2 + 24388^2 .

It is not a de Polignac number, because 688380169 - 2⁵ = 688380137 is a prime.

It is a super-2 number, since 2×688380169² = 947734514144937122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688180169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 13119 + ... + 39355.

Almost surely, 2^688380169 is an apocalyptic number.

688380169 is the 26237-th square number.

688380169 is the 13119-th centered octagonal number.

It is an amenable number.

688380169 is a deficient number, since it is larger than the sum of its proper divisors (26238).

688380169 is an frugal number, since it uses more digits than its factorization.

688380169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52474 (or 26237 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 49.

The cubic root of 688380169 is about 882.9635660217.

Multiplying 688380169 by its sum of digits (49), we get a square (33730628281 = 183659²).

The spelling of 688380169 in words is "six hundred eighty-eight million, three hundred eighty thousand, one hundred sixty-nine".