20657543 has 2 divisors, whose sum is σ = 20657544. Its totient is φ = 20657542.

The previous prime is 20657537. The next prime is 20657557. The reversal of 20657543 is 34575602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20657543 - 2¹² = 20653447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20657573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10328771 + 10328772.

It is an arithmetic number, because the mean of its divisors is an integer number (10328772).

Almost surely, 2^20657543 is an apocalyptic number.

20657543 is a deficient number, since it is larger than the sum of its proper divisors (1).

20657543 is an equidigital number, since it uses as much as digits as its factorization.

20657543 is an evil number, because the sum of its binary digits is even.

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

The square root of 20657543 is about 4545.0569853413. The cubic root of 20657543 is about 274.3844878353.

The spelling of 20657543 in words is "twenty million, six hundred fifty-seven thousand, five hundred forty-three".