21000982 has 4 divisors (see below), whose sum is σ = 31501476. Its totient is φ = 10500490.

The previous prime is 21000977. The next prime is 21000983. The reversal of 21000982 is 28900012.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5250244 + ... + 5250247.

It is an arithmetic number, because the mean of its divisors is an integer number (7875369).

Almost surely, 2^21000982 is an apocalyptic number.

21000982 is a deficient number, since it is larger than the sum of its proper divisors (10500494).

21000982 is a wasteful number, since it uses less digits than its factorization.

21000982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10500493.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 21000982 is about 4582.6828386874. The cubic root of 21000982 is about 275.8967179894.

Adding to 21000982 its reverse (28900012), we get a palindrome (49900994).

The spelling of 21000982 in words is "twenty-one million, nine hundred eighty-two", and thus it is an aban number.