21289489 has 8 divisors (see below), whose sum is σ = 23015552. Its totient is φ = 19576080.

The previous prime is 21289459. The next prime is 21289493. The reversal of 21289489 is 98498212.

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 21289489 - 2⁷ = 21289361 is a prime.

It is a super-2 number, since 2×21289489² = 906484683762242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21289409) 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, 502 + ... + 6544.

It is an arithmetic number, because the mean of its divisors is an integer number (2876944).

Almost surely, 2^21289489 is an apocalyptic number.

It is an amenable number.

21289489 is a deficient number, since it is larger than the sum of its proper divisors (1726063).

21289489 is a wasteful number, since it uses less digits than its factorization.

21289489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6327.

The product of its digits is 82944, while the sum is 43.

The square root of 21289489 is about 4614.0534240514. The cubic root of 21289489 is about 277.1543796610.

The spelling of 21289489 in words is "twenty-one million, two hundred eighty-nine thousand, four hundred eighty-nine".