6543989 has 2 divisors, whose sum is σ = 6543990. Its totient is φ = 6543988.

The previous prime is 6543973. The next prime is 6544003. The reversal of 6543989 is 9893456.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6543364 + 625 = 2558^2 + 25^2 .

It is a cyclic number.

It is not a de Polignac number, because 6543989 - 2⁴ = 6543973 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6543389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3271994 + 3271995.

It is an arithmetic number, because the mean of its divisors is an integer number (3271995).

Almost surely, 2^6543989 is an apocalyptic number.

It is an amenable number.

6543989 is a deficient number, since it is larger than the sum of its proper divisors (1).

6543989 is an equidigital number, since it uses as much as digits as its factorization.

6543989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 233280, while the sum is 44.

The square root of 6543989 is about 2558.1221628374. The cubic root of 6543989 is about 187.0456102344.

The spelling of 6543989 in words is "six million, five hundred forty-three thousand, nine hundred eighty-nine".