6661540 has 24 divisors (see below), whose sum is σ = 14055552. Its totient is φ = 2652000.

The previous prime is 6661511. The next prime is 6661547. The reversal of 6661540 is 451666.

It is a super-2 number, since 2×6661540² = 88752230343200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 6661499 and 6661508.

It is not an unprimeable number, because it can be changed into a prime (6661547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4357 + ... + 5683.

It is an arithmetic number, because the mean of its divisors is an integer number (585648).

Almost surely, 2^6661540 is an apocalyptic number.

It is an amenable number.

6661540 is an abundant number, since it is smaller than the sum of its proper divisors (7394012).

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

6661540 is a wasteful number, since it uses less digits than its factorization.

6661540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1587 (or 1585 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 6661540 is about 2580.9959318062. The cubic root of 6661540 is about 188.1589496240.

The spelling of 6661540 in words is "six million, six hundred sixty-one thousand, five hundred forty".