20556533 has 2 divisors, whose sum is σ = 20556534. Its totient is φ = 20556532.

The previous prime is 20556521. The next prime is 20556541. The reversal of 20556533 is 33565502.

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., 16957924 + 3598609 = 4118^2 + 1897^2 .

It is a cyclic number.

It is not a de Polignac number, because 20556533 - 2⁴ = 20556517 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20556496 and 20556505.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20556433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278266 + 10278267.

It is an arithmetic number, because the mean of its divisors is an integer number (10278267).

Almost surely, 2^20556533 is an apocalyptic number.

It is an amenable number.

20556533 is a deficient number, since it is larger than the sum of its proper divisors (1).

20556533 is an equidigital number, since it uses as much as digits as its factorization.

20556533 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13500, while the sum is 29.

The square root of 20556533 is about 4533.9312963476. The cubic root of 20556533 is about 273.9365340424.

The spelling of 20556533 in words is "twenty million, five hundred fifty-six thousand, five hundred thirty-three".