21988384 has 24 divisors (see below), whose sum is σ = 47225808. Its totient is φ = 9994560.

The previous prime is 21988367. The next prime is 21988387. The reversal of 21988384 is 48388912.

It is a self number, because there is not a number n which added to its sum of digits gives 21988384.

It is not an unprimeable number, because it can be changed into a prime (21988387) 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, 30882 + ... + 31585.

It is an arithmetic number, because the mean of its divisors is an integer number (1967742).

Almost surely, 2^21988384 is an apocalyptic number.

It is an amenable number.

21988384 is an abundant number, since it is smaller than the sum of its proper divisors (25237424).

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

21988384 is a wasteful number, since it uses less digits than its factorization.

21988384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62488 (or 62480 counting only the distinct ones).

The product of its digits is 110592, while the sum is 43.

The square root of 21988384 is about 4689.1773265681. The cubic root of 21988384 is about 280.1546084912.

The spelling of 21988384 in words is "twenty-one million, nine hundred eighty-eight thousand, three hundred eighty-four".