21145889 has 8 divisors (see below), whose sum is σ = 21468480. Its totient is φ = 20826000.

The previous prime is 21145871. The next prime is 21145919. The reversal of 21145889 is 98854112.

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

It is a cyclic number.

It is not a de Polignac number, because 21145889 - 2¹² = 21141793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21145829) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19247 + ... + 20315.

It is an arithmetic number, because the mean of its divisors is an integer number (2683560).

Almost surely, 2^21145889 is an apocalyptic number.

It is an amenable number.

21145889 is a deficient number, since it is larger than the sum of its proper divisors (322591).

21145889 is a wasteful number, since it uses less digits than its factorization.

21145889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1351.

The product of its digits is 23040, while the sum is 38.

The square root of 21145889 is about 4598.4659398543. The cubic root of 21145889 is about 276.5298274936.

The spelling of 21145889 in words is "twenty-one million, one hundred forty-five thousand, eight hundred eighty-nine".