21273427 has 4 divisors (see below), whose sum is σ = 24312496. Its totient is φ = 18234360.

The previous prime is 21273391. The next prime is 21273431. The reversal of 21273427 is 72437212.

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

It is a cyclic number.

It is not a de Polignac number, because 21273427 - 2¹¹ = 21271379 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21273395 and 21273404.

It is not an unprimeable number, because it can be changed into a prime (21273437) 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, 1519524 + ... + 1519537.

It is an arithmetic number, because the mean of its divisors is an integer number (6078124).

Almost surely, 2^21273427 is an apocalyptic number.

21273427 is a deficient number, since it is larger than the sum of its proper divisors (3039069).

21273427 is an equidigital number, since it uses as much as digits as its factorization.

21273427 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3039068.

The product of its digits is 4704, while the sum is 28.

The square root of 21273427 is about 4612.3125436163. The cubic root of 21273427 is about 277.0846617885.

The spelling of 21273427 in words is "twenty-one million, two hundred seventy-three thousand, four hundred twenty-seven".