64191789 has 6 divisors (see below), whose sum is σ = 92721486. Its totient is φ = 42794520.

The previous prime is 64191737. The next prime is 64191791. The reversal of 64191789 is 98719146.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 62678889 + 1512900 = 7917^2 + 1230^2 .

It is not a de Polignac number, because 64191789 - 2⁹ = 64191277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64191719) 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 in 5 ways as a sum of consecutive naturals, for example, 3566202 + ... + 3566219.

It is an arithmetic number, because the mean of its divisors is an integer number (15453581).

Almost surely, 2^64191789 is an apocalyptic number.

It is an amenable number.

64191789 is a deficient number, since it is larger than the sum of its proper divisors (28529697).

64191789 is a wasteful number, since it uses less digits than its factorization.

64191789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7132427 (or 7132424 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 64191789 is about 8011.9778457008. The cubic root of 64191789 is about 400.3991619585.

It can be divided in two parts, 64191 and 789, that added together give a triangular number (64980 = T₃₆₀).

The spelling of 64191789 in words is "sixty-four million, one hundred ninety-one thousand, seven hundred eighty-nine".