21273245 has 16 divisors (see below), whose sum is σ = 29267328. Its totient is φ = 14541120.

The previous prime is 21273191. The next prime is 21273253. The reversal of 21273245 is 54237212.

It is not a de Polignac number, because 21273245 - 2⁶ = 21273181 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13130 + ... + 14660.

It is an arithmetic number, because the mean of its divisors is an integer number (1829208).

Almost surely, 2^21273245 is an apocalyptic number.

It is an amenable number.

21273245 is a deficient number, since it is larger than the sum of its proper divisors (7994083).

21273245 is a wasteful number, since it uses less digits than its factorization.

21273245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1940.

The product of its digits is 3360, while the sum is 26.

The square root of 21273245 is about 4612.2928137749. The cubic root of 21273245 is about 277.0838716078.

The spelling of 21273245 in words is "twenty-one million, two hundred seventy-three thousand, two hundred forty-five".