21147073 has 2 divisors, whose sum is σ = 21147074. Its totient is φ = 21147072.

The previous prime is 21147059. The next prime is 21147079. The reversal of 21147073 is 37074112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18766224 + 2380849 = 4332^2 + 1543^2 .

It is a cyclic number.

It is not a de Polignac number, because 21147073 - 2⁹ = 21146561 is a prime.

It is not a weakly prime, because it can be changed into another prime (21147079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10573536 + 10573537.

It is an arithmetic number, because the mean of its divisors is an integer number (10573537).

Almost surely, 2^21147073 is an apocalyptic number.

It is an amenable number.

21147073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21147073 is an equidigital number, since it uses as much as digits as its factorization.

21147073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1176, while the sum is 25.

The square root of 21147073 is about 4598.5946766376. The cubic root of 21147073 is about 276.5349885473.

Multiplying 21147073 by its sum of digits (25), we get a palindrome (528676825).

The spelling of 21147073 in words is "twenty-one million, one hundred forty-seven thousand, seventy-three".