18969984 has 128 divisors (see below), whose sum is σ = 61200000. Its totient is φ = 5736960.

The previous prime is 18969983. The next prime is 18969997. The reversal of 18969984 is 48996981.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 18969984.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18969983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37767 + ... + 38265.

It is an arithmetic number, because the mean of its divisors is an integer number (478125).

Almost surely, 2^18969984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18969984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30600000).

18969984 is an abundant number, since it is smaller than the sum of its proper divisors (42230016).

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

18969984 is a wasteful number, since it uses less digits than its factorization.

18969984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533 (or 515 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 54.

The square root of 18969984 is about 4355.4545112996. The cubic root of 18969984 is about 266.6995737168.

The spelling of 18969984 in words is "eighteen million, nine hundred sixty-nine thousand, nine hundred eighty-four".