64691689 has 2 divisors, whose sum is σ = 64691690. Its totient is φ = 64691688.

The previous prime is 64691657. The next prime is 64691701. The reversal of 64691689 is 98619646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47610000 + 17081689 = 6900^2 + 4133^2 .

It is a cyclic number.

It is not a de Polignac number, because 64691689 - 2⁵ = 64691657 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (64691629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32345844 + 32345845.

It is an arithmetic number, because the mean of its divisors is an integer number (32345845).

Almost surely, 2^64691689 is an apocalyptic number.

It is an amenable number.

64691689 is a deficient number, since it is larger than the sum of its proper divisors (1).

64691689 is an equidigital number, since it uses as much as digits as its factorization.

64691689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 559872, while the sum is 49.

The square root of 64691689 is about 8043.1143843663. The cubic root of 64691689 is about 401.4358583596.

The spelling of 64691689 in words is "sixty-four million, six hundred ninety-one thousand, six hundred eighty-nine".