21040273 has 4 divisors (see below), whose sum is σ = 21134848. Its totient is φ = 20945700.

The previous prime is 21040267. The next prime is 21040297. The reversal of 21040273 is 37204012.

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 21040273 - 2²¹ = 18943121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21040273.

It is not an unprimeable number, because it can be changed into a prime (21040213) 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, 46953 + ... + 47398.

It is an arithmetic number, because the mean of its divisors is an integer number (5283712).

Almost surely, 2^21040273 is an apocalyptic number.

It is an amenable number.

21040273 is a deficient number, since it is larger than the sum of its proper divisors (94575).

21040273 is an equidigital number, since it uses as much as digits as its factorization.

21040273 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94574.

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 21040273 is about 4586.9677347895. The cubic root of 21040273 is about 276.0686703386.

Adding to 21040273 its reverse (37204012), we get a palindrome (58244285).

The spelling of 21040273 in words is "twenty-one million, forty thousand, two hundred seventy-three".