21302989 has 8 divisors (see below), whose sum is σ = 22674168. Its totient is φ = 19944960.

The previous prime is 21302947. The next prime is 21302993. The reversal of 21302989 is 98920312.

It can be written as a sum of positive squares in 4 ways, for example, as 9455625 + 11847364 = 3075^2 + 3442^2 .

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 21302989 - 2¹¹ = 21300941 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 (21302909) 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, 169 + ... + 6529.

It is an arithmetic number, because the mean of its divisors is an integer number (2834271).

Almost surely, 2^21302989 is an apocalyptic number.

It is an amenable number.

21302989 is a deficient number, since it is larger than the sum of its proper divisors (1371179).

21302989 is a wasteful number, since it uses less digits than its factorization.

21302989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6575.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 21302989 is about 4615.5161141523. The cubic root of 21302989 is about 277.2129499339.

The spelling of 21302989 in words is "twenty-one million, three hundred two thousand, nine hundred eighty-nine".