21259373 has 2 divisors, whose sum is σ = 21259374. Its totient is φ = 21259372.

The previous prime is 21259363. The next prime is 21259387. The reversal of 21259373 is 37395212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20097289 + 1162084 = 4483^2 + 1078^2 .

It is a cyclic number.

It is not a de Polignac number, because 21259373 - 2¹² = 21255277 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21259313) 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, 10629686 + 10629687.

It is an arithmetic number, because the mean of its divisors is an integer number (10629687).

Almost surely, 2^21259373 is an apocalyptic number.

It is an amenable number.

21259373 is a deficient number, since it is larger than the sum of its proper divisors (1).

21259373 is an equidigital number, since it uses as much as digits as its factorization.

21259373 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11340, while the sum is 32.

The square root of 21259373 is about 4610.7887611557. The cubic root of 21259373 is about 277.0236309433.

The spelling of 21259373 in words is "twenty-one million, two hundred fifty-nine thousand, three hundred seventy-three".