15561984 has 72 divisors (see below), whose sum is σ = 43267392. Its totient is φ = 4956160.

The previous prime is 15561983. The next prime is 15561989. The reversal of 15561984 is 48916551.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15561983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17224 + ... + 18104.

It is an arithmetic number, because the mean of its divisors is an integer number (600936).

Almost surely, 2^15561984 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 15561984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21633696).

15561984 is an abundant number, since it is smaller than the sum of its proper divisors (27705408).

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

15561984 is an equidigital number, since it uses as much as digits as its factorization.

15561984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 923 (or 909 counting only the distinct ones).

The product of its digits is 43200, while the sum is 39.

The square root of 15561984 is about 3944.8680586301. The cubic root of 15561984 is about 249.6634618382.

The spelling of 15561984 in words is "fifteen million, five hundred sixty-one thousand, nine hundred eighty-four".