21143389 has 4 divisors (see below), whose sum is σ = 21160224. Its totient is φ = 21126556.

The previous prime is 21143383. The next prime is 21143411. The reversal of 21143389 is 98334112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21143389 - 2⁵ = 21143357 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21143389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21143383) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6367 + ... + 9100.

It is an arithmetic number, because the mean of its divisors is an integer number (5290056).

Almost surely, 2^21143389 is an apocalyptic number.

It is an amenable number.

21143389 is a deficient number, since it is larger than the sum of its proper divisors (16835).

21143389 is a wasteful number, since it uses less digits than its factorization.

21143389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16834.

The product of its digits is 5184, while the sum is 31.

The square root of 21143389 is about 4598.1941020361. The cubic root of 21143389 is about 276.5189293656.

The spelling of 21143389 in words is "twenty-one million, one hundred forty-three thousand, three hundred eighty-nine".