19664749 has 8 divisors (see below), whose sum is σ = 21577752. Its totient is φ = 17808960.

The previous prime is 19664741. The next prime is 19664779. The reversal of 19664749 is 94746691.

It can be written as a sum of positive squares in 4 ways, for example, as 611524 + 19053225 = 782^2 + 4365^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 19664749 - 2³ = 19664741 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19664699 and 19664708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19664741) 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 in 7 ways as a sum of consecutive naturals, for example, 13582 + ... + 14959.

It is an arithmetic number, because the mean of its divisors is an integer number (2697219).

Almost surely, 2^19664749 is an apocalyptic number.

It is an amenable number.

19664749 is a deficient number, since it is larger than the sum of its proper divisors (1913003).

19664749 is a wasteful number, since it uses less digits than its factorization.

19664749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28607.

The product of its digits is 326592, while the sum is 46.

The square root of 19664749 is about 4434.4953489659. The cubic root of 19664749 is about 269.9165219755.

The spelling of 19664749 in words is "nineteen million, six hundred sixty-four thousand, seven hundred forty-nine".