21013983 has 12 divisors (see below), whose sum is σ = 30667728. Its totient is φ = 13864320.

The previous prime is 21013961. The next prime is 21013987. The reversal of 21013983 is 38931012.

It is not a de Polignac number, because 21013983 - 2¹² = 21009887 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11163 + ... + 12908.

It is an arithmetic number, because the mean of its divisors is an integer number (2555644).

Almost surely, 2^21013983 is an apocalyptic number.

21013983 is a deficient number, since it is larger than the sum of its proper divisors (9653745).

21013983 is a wasteful number, since it uses less digits than its factorization.

21013983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24174 (or 24171 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 21013983 is about 4584.1011114503. The cubic root of 21013983 is about 275.9536390309.

Adding to 21013983 its reverse (38931012), we get a palindrome (59944995).

It can be divided in two parts, 2101 and 3983, that added together give a square (6084 = 78²).

The spelling of 21013983 in words is "twenty-one million, thirteen thousand, nine hundred eighty-three".