19809664 has 32 divisors (see below), whose sum is σ = 45104400. Its totient is φ = 8489472.

The previous prime is 19809653. The next prime is 19809667. The reversal of 19809664 is 46690891.

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 19809664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19809667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10159 + ... + 11950.

Almost surely, 2^19809664 is an apocalyptic number.

19809664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

19809664 is an abundant number, since it is smaller than the sum of its proper divisors (25294736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19809664 is an equidigital number, since it uses as much as digits as its factorization.

19809664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22130 (or 22118 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 19809664 is about 4450.8048710318. The cubic root of 19809664 is about 270.5779298792.

The spelling of 19809664 in words is "nineteen million, eight hundred nine thousand, six hundred sixty-four".