6545243021 has 4 divisors (see below), whose sum is σ = 6547998972. Its totient is φ = 6542487072.

The previous prime is 6545243017. The next prime is 6545243027. The reversal of 6545243021 is 1203425456.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2979958921 + 3565284100 = 54589^2 + 59710^2 .

It is a cyclic number.

It is not a de Polignac number, because 6545243021 - 2² = 6545243017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6545243027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1374410 + ... + 1379163.

It is an arithmetic number, because the mean of its divisors is an integer number (1636999743).

Almost surely, 2^6545243021 is an apocalyptic number.

It is an amenable number.

6545243021 is a deficient number, since it is larger than the sum of its proper divisors (2755951).

6545243021 is a wasteful number, since it uses less digits than its factorization.

6545243021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2755950.

The product of its (nonzero) digits is 28800, while the sum is 32.

The square root of 6545243021 is about 80902.6762289110. The cubic root of 6545243021 is about 1870.5755728698.

Adding to 6545243021 its reverse (1203425456), we get a palindrome (7748668477).

The spelling of 6545243021 in words is "six billion, five hundred forty-five million, two hundred forty-three thousand, twenty-one".