21040189 has 4 divisors (see below), whose sum is σ = 21179680. Its totient is φ = 20900700.

The previous prime is 21040183. The next prime is 21040199. The reversal of 21040189 is 98104012.

It is a happy number.

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 21040189 - 2⁵ = 21040157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040183) 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, 69519 + ... + 69820.

It is an arithmetic number, because the mean of its divisors is an integer number (5294920).

Almost surely, 2^21040189 is an apocalyptic number.

It is an amenable number.

21040189 is a deficient number, since it is larger than the sum of its proper divisors (139491).

21040189 is a wasteful number, since it uses less digits than its factorization.

21040189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139490.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 21040189 is about 4586.9585784046. The cubic root of 21040189 is about 276.0683029511.

The spelling of 21040189 in words is "twenty-one million, forty thousand, one hundred eighty-nine".