21225473 has 2 divisors, whose sum is σ = 21225474. Its totient is φ = 21225472.

The previous prime is 21225437. The next prime is 21225487. The reversal of 21225473 is 37452212.

Together with previous prime (21225437) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21224449 + 1024 = 4607^2 + 32^2 .

It is a cyclic number.

It is not a de Polignac number, because 21225473 - 2¹² = 21221377 is a prime.

It is not a weakly prime, because it can be changed into another prime (21225403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612736 + 10612737.

It is an arithmetic number, because the mean of its divisors is an integer number (10612737).

It is a Proth number, since it is equal to 2591 ⋅ 2¹³ + 1 and 2591 < 2¹³.

Almost surely, 2^21225473 is an apocalyptic number.

It is an amenable number.

21225473 is a deficient number, since it is larger than the sum of its proper divisors (1).

21225473 is an equidigital number, since it uses as much as digits as its factorization.

21225473 is an evil number, because the sum of its binary digits is even.

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

The square root of 21225473 is about 4607.1111338886. Note that the first 4 decimals coincide. The cubic root of 21225473 is about 276.8763061661.

Adding to 21225473 its reverse (37452212), we get a palindrome (58677685).

The spelling of 21225473 in words is "twenty-one million, two hundred twenty-five thousand, four hundred seventy-three".