6561879520 has 96 divisors (see below), whose sum is σ = 18649612800. Its totient is φ = 2131370496.

The previous prime is 6561879517. The next prime is 6561879559. The reversal of 6561879520 is 259781656.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 132900 + ... + 175459.

It is an arithmetic number, because the mean of its divisors is an integer number (194266800).

Almost surely, 2^6561879520 is an apocalyptic number.

It is an amenable number.

6561879520 is an abundant number, since it is smaller than the sum of its proper divisors (12087733280).

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

6561879520 is a wasteful number, since it uses less digits than its factorization.

6561879520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308400 (or 308392 counting only the distinct ones).

The product of its (nonzero) digits is 907200, while the sum is 49.

The square root of 6561879520 is about 81005.4289538670. The cubic root of 6561879520 is about 1872.1590892872.

The spelling of 6561879520 in words is "six billion, five hundred sixty-one million, eight hundred seventy-nine thousand, five hundred twenty".