20533309 has 2 divisors, whose sum is σ = 20533310. Its totient is φ = 20533308.

The previous prime is 20533307. The next prime is 20533321. The reversal of 20533309 is 90333502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14516100 + 6017209 = 3810^2 + 2453^2 .

It is a cyclic number.

It is not a de Polignac number, because 20533309 - 2¹ = 20533307 is a prime.

Together with 20533307, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20533307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10266654 + 10266655.

It is an arithmetic number, because the mean of its divisors is an integer number (10266655).

Almost surely, 2^20533309 is an apocalyptic number.

It is an amenable number.

20533309 is a deficient number, since it is larger than the sum of its proper divisors (1).

20533309 is an equidigital number, since it uses as much as digits as its factorization.

20533309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2430, while the sum is 25.

The square root of 20533309 is about 4531.3694398051. The cubic root of 20533309 is about 273.8333340948.

The spelling of 20533309 in words is "twenty million, five hundred thirty-three thousand, three hundred nine".