688194449 has 2 divisors, whose sum is σ = 688194450. Its totient is φ = 688194448.

The previous prime is 688194439. The next prime is 688194469. The reversal of 688194449 is 944491886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 682881424 + 5313025 = 26132^2 + 2305^2 .

It is a cyclic number.

It is not a de Polignac number, because 688194449 - 2¹⁶ = 688128913 is a prime.

It is a super-2 number, since 2×688194449² = 947223199268827202, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 688194449.

It is not a weakly prime, because it can be changed into another prime (688194439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344097224 + 344097225.

It is an arithmetic number, because the mean of its divisors is an integer number (344097225).

Almost surely, 2^688194449 is an apocalyptic number.

It is an amenable number.

688194449 is a deficient number, since it is larger than the sum of its proper divisors (1).

688194449 is an equidigital number, since it uses as much as digits as its factorization.

688194449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1990656, while the sum is 53.

The square root of 688194449 is about 26233.4604846559. The cubic root of 688194449 is about 882.8841531477.

The spelling of 688194449 in words is "six hundred eighty-eight million, one hundred ninety-four thousand, four hundred forty-nine".