21273243 has 8 divisors (see below), whose sum is σ = 28438800. Its totient is φ = 14144928.

The previous prime is 21273191. The next prime is 21273253. The reversal of 21273243 is 34237212.

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

It is not a de Polignac number, because 21273243 - 2⁸ = 21272987 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21273253) 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, 7948 + ... + 10281.

It is an arithmetic number, because the mean of its divisors is an integer number (3554850).

Almost surely, 2^21273243 is an apocalyptic number.

21273243 is a deficient number, since it is larger than the sum of its proper divisors (7165557).

21273243 is a wasteful number, since it uses less digits than its factorization.

21273243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18621.

The product of its digits is 2016, while the sum is 24.

The square root of 21273243 is about 4612.2925969630. The cubic root of 21273243 is about 277.0838629245.

The spelling of 21273243 in words is "twenty-one million, two hundred seventy-three thousand, two hundred forty-three".