6561520 has 40 divisors (see below), whose sum is σ = 17436384. Its totient is φ = 2249472.

The previous prime is 6561497. The next prime is 6561521. The reversal of 6561520 is 251656.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5299 + ... + 6418.

Almost surely, 2^6561520 is an apocalyptic number.

It is an amenable number.

6561520 is an abundant number, since it is smaller than the sum of its proper divisors (10874864).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6561520 is a wasteful number, since it uses less digits than its factorization.

6561520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11737 (or 11731 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 6561520 is about 2561.5464079341. The cubic root of 6561520 is about 187.2124897309.

The spelling of 6561520 in words is "six million, five hundred sixty-one thousand, five hundred twenty".