19891064 has 8 divisors (see below), whose sum is σ = 37295760. Its totient is φ = 9945528.

The previous prime is 19891061. The next prime is 19891073. The reversal of 19891064 is 46019891.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19891061) 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 as a sum of consecutive naturals, namely, 1243184 + ... + 1243199.

It is an arithmetic number, because the mean of its divisors is an integer number (4661970).

Almost surely, 2^19891064 is an apocalyptic number.

It is an amenable number.

19891064 is a deficient number, since it is larger than the sum of its proper divisors (17404696).

19891064 is a wasteful number, since it uses less digits than its factorization.

19891064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2486389 (or 2486385 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 19891064 is about 4459.9399099091. The cubic root of 19891064 is about 270.9480344980.

The spelling of 19891064 in words is "nineteen million, eight hundred ninety-one thousand, sixty-four".