6561207220 has 24 divisors (see below), whose sum is σ = 13789036800. Its totient is φ = 2622482592.

The previous prime is 6561207203. The next prime is 6561207227. The reversal of 6561207220 is 227021656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561207227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97980 + ... + 150739.

It is an arithmetic number, because the mean of its divisors is an integer number (574543200).

Almost surely, 2^6561207220 is an apocalyptic number.

It is an amenable number.

6561207220 is an abundant number, since it is smaller than the sum of its proper divisors (7227829580).

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

6561207220 is a wasteful number, since it uses less digits than its factorization.

6561207220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250047 (or 250045 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 6561207220 is about 81001.2791257027. The cubic root of 6561207220 is about 1872.0951494999.

Adding to 6561207220 its reverse (227021656), we get a palindrome (6788228876).

The spelling of 6561207220 in words is "six billion, five hundred sixty-one million, two hundred seven thousand, two hundred twenty".