21280238 has 16 divisors (see below), whose sum is σ = 37100160. Its totient is φ = 8965176.

The previous prime is 21280223. The next prime is 21280241. The reversal of 21280238 is 83208212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12056 + ... + 13707.

It is an arithmetic number, because the mean of its divisors is an integer number (2318760).

Almost surely, 2^21280238 is an apocalyptic number.

21280238 is a deficient number, since it is larger than the sum of its proper divisors (15819922).

21280238 is a wasteful number, since it uses less digits than its factorization.

21280238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25831.

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 21280238 is about 4613.0508343178. The cubic root of 21280238 is about 277.1142295408.

The spelling of 21280238 in words is "twenty-one million, two hundred eighty thousand, two hundred thirty-eight".