20556743 has 2 divisors, whose sum is σ = 20556744. Its totient is φ = 20556742.

The previous prime is 20556707. The next prime is 20556769. The reversal of 20556743 is 34765502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20556743 - 2¹² = 20552647 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20558743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278371 + 10278372.

It is an arithmetic number, because the mean of its divisors is an integer number (10278372).

Almost surely, 2^20556743 is an apocalyptic number.

20556743 is a deficient number, since it is larger than the sum of its proper divisors (1).

20556743 is an equidigital number, since it uses as much as digits as its factorization.

20556743 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 32.

The square root of 20556743 is about 4533.9544549984. The cubic root of 20556743 is about 273.9374668598.

The spelling of 20556743 in words is "twenty million, five hundred fifty-six thousand, seven hundred forty-three".