20720543 has 2 divisors, whose sum is σ = 20720544. Its totient is φ = 20720542.

The previous prime is 20720533. The next prime is 20720549. The reversal of 20720543 is 34502702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20720543 - 2⁴ = 20720527 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20720549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10360271 + 10360272.

It is an arithmetic number, because the mean of its divisors is an integer number (10360272).

Almost surely, 2^20720543 is an apocalyptic number.

20720543 is a deficient number, since it is larger than the sum of its proper divisors (1).

20720543 is an equidigital number, since it uses as much as digits as its factorization.

20720543 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1680, while the sum is 23.

The square root of 20720543 is about 4551.9823154314. The cubic root of 20720543 is about 274.6631379415.

The spelling of 20720543 in words is "twenty million, seven hundred twenty thousand, five hundred forty-three".