21293289 has 6 divisors (see below), whose sum is σ = 30756986. Its totient is φ = 14195520.

The previous prime is 21293273. The next prime is 21293317. The reversal of 21293289 is 98239212.

It can be written as a sum of positive squares in only one way, i.e., 16040025 + 5253264 = 4005^2 + 2292^2 .

It is not a de Polignac number, because 21293289 - 2⁴ = 21293273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21293089) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1182952 + ... + 1182969.

Almost surely, 2^21293289 is an apocalyptic number.

It is an amenable number.

21293289 is a deficient number, since it is larger than the sum of its proper divisors (9463697).

21293289 is a wasteful number, since it uses less digits than its factorization.

21293289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2365927 (or 2365924 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21293289 is about 4614.4651911137. The cubic root of 21293289 is about 277.1708686115.

The spelling of 21293289 in words is "twenty-one million, two hundred ninety-three thousand, two hundred eighty-nine".