21275273 has 4 divisors (see below), whose sum is σ = 21291648. Its totient is φ = 21258900.

The previous prime is 21275237. The next prime is 21275281. The reversal of 21275273 is 37257212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21275273 - 2⁶ = 21275209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21275203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6053 + ... + 8898.

It is an arithmetic number, because the mean of its divisors is an integer number (5322912).

Almost surely, 2^21275273 is an apocalyptic number.

It is an amenable number.

21275273 is a deficient number, since it is larger than the sum of its proper divisors (16375).

21275273 is a wasteful number, since it uses less digits than its factorization.

21275273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16374.

The product of its digits is 5880, while the sum is 29.

The square root of 21275273 is about 4612.5126558092. The cubic root of 21275273 is about 277.0926762234.

The spelling of 21275273 in words is "twenty-one million, two hundred seventy-five thousand, two hundred seventy-three".