6561959040 has 960 divisors, whose sum is σ = 29271274560. Its totient is φ = 1371561984.

The previous prime is 6561959017. The next prime is 6561959071. The reversal of 6561959040 is 409591656.

It is a happy number.

6561959040 is a `hidden beast` number, since 6 + 5 + 6 + 19 + 590 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 61326667 + ... + 61326773.

It is an arithmetic number, because the mean of its divisors is an integer number (30490911).

Almost surely, 2^6561959040 is an apocalyptic number.

6561959040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6561959040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14635637280).

6561959040 is an abundant number, since it is smaller than the sum of its proper divisors (22709315520).

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

6561959040 is a wasteful number, since it uses less digits than its factorization.

6561959040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 291600, while the sum is 45.

The square root of 6561959040 is about 81005.9197836800. The cubic root of 6561959040 is about 1872.1666518303.

The spelling of 6561959040 in words is "six billion, five hundred sixty-one million, nine hundred fifty-nine thousand, forty".