21273361 has 4 divisors (see below), whose sum is σ = 21492772. Its totient is φ = 21053952.

The previous prime is 21273359. The next prime is 21273391. The reversal of 21273361 is 16337212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17172736 + 4100625 = 4144^2 + 2025^2 .

It is a cyclic number.

It is not a de Polignac number, because 21273361 - 2¹ = 21273359 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21273391) 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, 109560 + ... + 109753.

It is an arithmetic number, because the mean of its divisors is an integer number (5373193).

Almost surely, 2^21273361 is an apocalyptic number.

It is an amenable number.

21273361 is a deficient number, since it is larger than the sum of its proper divisors (219411).

21273361 is an equidigital number, since it uses as much as digits as its factorization.

21273361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219410.

The product of its digits is 1512, while the sum is 25.

The square root of 21273361 is about 4612.3053888484. The cubic root of 21273361 is about 277.0843752400.

The spelling of 21273361 in words is "twenty-one million, two hundred seventy-three thousand, three hundred sixty-one".