21072189 has 8 divisors (see below), whose sum is σ = 28138720. Its totient is φ = 14026896.

The previous prime is 21072187. The next prime is 21072199. The reversal of 21072189 is 98127012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21072189 - 2¹ = 21072187 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21072187) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2827 + ... + 7080.

It is an arithmetic number, because the mean of its divisors is an integer number (3517340).

Almost surely, 2^21072189 is an apocalyptic number.

It is an amenable number.

21072189 is a deficient number, since it is larger than the sum of its proper divisors (7066531).

21072189 is an equidigital number, since it uses as much as digits as its factorization.

21072189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10619.

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21072189 is about 4590.4454032261. The cubic root of 21072189 is about 276.2081893821.

The spelling of 21072189 in words is "twenty-one million, seventy-two thousand, one hundred eighty-nine".