21443013 has 6 divisors (see below), whose sum is σ = 30973254. Its totient is φ = 14295336.

The previous prime is 21443003. The next prime is 21443033. The reversal of 21443013 is 31034412.

It can be written as a sum of positive squares in only one way, i.e., 17994564 + 3448449 = 4242^2 + 1857^2 .

It is not a de Polignac number, because 21443013 - 2⁹ = 21442501 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443003) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1191270 + ... + 1191287.

It is an arithmetic number, because the mean of its divisors is an integer number (5162209).

Almost surely, 2^21443013 is an apocalyptic number.

It is an amenable number.

21443013 is a deficient number, since it is larger than the sum of its proper divisors (9530241).

21443013 is a wasteful number, since it uses less digits than its factorization.

21443013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2382563 (or 2382560 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21443013 is about 4630.6601041320. The cubic root of 21443013 is about 277.8189952289.

Adding to 21443013 its reverse (31034412), we get a palindrome (52477425).

The spelling of 21443013 in words is "twenty-one million, four hundred forty-three thousand, thirteen".