6561660601 has 16 divisors (see below), whose sum is σ = 6932459520. Its totient is φ = 6201898560.

The previous prime is 6561660571. The next prime is 6561660607. The reversal of 6561660601 is 1060661656.

It is a cyclic number.

It is not a de Polignac number, because 6561660601 - 2¹⁵ = 6561627833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6561660607) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 357435 + ... + 375343.

It is an arithmetic number, because the mean of its divisors is an integer number (433278720).

Almost surely, 2^6561660601 is an apocalyptic number.

It is an amenable number.

6561660601 is a deficient number, since it is larger than the sum of its proper divisors (370798919).

6561660601 is a wasteful number, since it uses less digits than its factorization.

6561660601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18216.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 6561660601 is about 81004.0776813118. The cubic root of 6561660601 is about 1872.1382692487.

The spelling of 6561660601 in words is "six billion, five hundred sixty-one million, six hundred sixty thousand, six hundred one".