6561940 has 48 divisors (see below), whose sum is σ = 17184384. Its totient is φ = 2044800.

The previous prime is 6561937. The next prime is 6561941. The reversal of 6561940 is 491656.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 591 + ... + 3670.

It is an arithmetic number, because the mean of its divisors is an integer number (358008).

Almost surely, 2^6561940 is an apocalyptic number.

It is an amenable number.

6561940 is an abundant number, since it is smaller than the sum of its proper divisors (10622444).

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

6561940 is a wasteful number, since it uses less digits than its factorization.

6561940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4288 (or 4286 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 6561940 is about 2561.6283883499. The cubic root of 6561940 is about 187.2164841086.

The spelling of 6561940 in words is "six million, five hundred sixty-one thousand, nine hundred forty".