21002984 has 32 divisors (see below), whose sum is σ = 40763520. Its totient is φ = 10139136.

The previous prime is 21002983. The next prime is 21002987. The reversal of 21002984 is 48920012.

It is a super-2 number, since 2×21002984² = 882250673808512, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21002981) 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, 30872 + ... + 31544.

It is an arithmetic number, because the mean of its divisors is an integer number (1273860).

Almost surely, 2^21002984 is an apocalyptic number.

It is an amenable number.

21002984 is a deficient number, since it is larger than the sum of its proper divisors (19760536).

21002984 is a wasteful number, since it uses less digits than its factorization.

21002984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 809 (or 805 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 21002984 is about 4582.9012644830. The cubic root of 21002984 is about 275.9054846855.

Adding to 21002984 its reverse (48920012), we get a palindrome (69922996).

The spelling of 21002984 in words is "twenty-one million, two thousand, nine hundred eighty-four".