21442984 has 16 divisors (see below), whose sum is σ = 42570900. Its totient is φ = 10090752.

The previous prime is 21442957. The next prime is 21442987. The reversal of 21442984 is 48924412.

It can be written as a sum of positive squares in 2 ways, for example, as 21436900 + 6084 = 4630^2 + 78^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is not an unprimeable number, because it can be changed into a prime (21442987) 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 3 ways as a sum of consecutive naturals, for example, 78699 + ... + 78970.

Almost surely, 2^21442984 is an apocalyptic number.

It is an amenable number.

21442984 is a deficient number, since it is larger than the sum of its proper divisors (21127916).

21442984 is a wasteful number, since it uses less digits than its factorization.

21442984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157692 (or 157688 counting only the distinct ones).

The product of its digits is 18432, while the sum is 34.

The square root of 21442984 is about 4630.6569728279. The cubic root of 21442984 is about 277.8188699860.

The spelling of 21442984 in words is "twenty-one million, four hundred forty-two thousand, nine hundred eighty-four".