21247089 has 8 divisors (see below), whose sum is σ = 28359552. Its totient is φ = 14149680.

The previous prime is 21247081. The next prime is 21247103. The reversal of 21247089 is 98074212.

It is a happy number.

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

It is not a de Polignac number, because 21247089 - 2³ = 21247081 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21247081) 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, 99 + ... + 6519.

It is an arithmetic number, because the mean of its divisors is an integer number (3544944).

Almost surely, 2^21247089 is an apocalyptic number.

It is an amenable number.

21247089 is a deficient number, since it is larger than the sum of its proper divisors (7112463).

21247089 is a wasteful number, since it uses less digits than its factorization.

21247089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7527.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 21247089 is about 4609.4564755511. The cubic root of 21247089 is about 276.9702644600.

The spelling of 21247089 in words is "twenty-one million, two hundred forty-seven thousand, eighty-nine".