689909749 has 2 divisors, whose sum is σ = 689909750. Its totient is φ = 689909748.

The previous prime is 689909729. The next prime is 689909761. The reversal of 689909749 is 947909986.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 447111025 + 242798724 = 21145^2 + 15582^2 .

It is a cyclic number.

It is not a de Polignac number, because 689909749 - 2⁹ = 689909237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (689909729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344954874 + 344954875.

It is an arithmetic number, because the mean of its divisors is an integer number (344954875).

Almost surely, 2^689909749 is an apocalyptic number.

It is an amenable number.

689909749 is a deficient number, since it is larger than the sum of its proper divisors (1).

689909749 is an equidigital number, since it uses as much as digits as its factorization.

689909749 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8817984, while the sum is 61.

The square root of 689909749 is about 26266.1331185236. The cubic root of 689909749 is about 883.6170636035.

The spelling of 689909749 in words is "six hundred eighty-nine million, nine hundred nine thousand, seven hundred forty-nine".