6621540 has 24 divisors (see below), whose sum is σ = 18540480. Its totient is φ = 1765728.

The previous prime is 6621533. The next prime is 6621553. The reversal of 6621540 is 451266.

It is a self number, because there is not a number n which added to its sum of digits gives 6621540.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55120 + ... + 55239.

It is an arithmetic number, because the mean of its divisors is an integer number (772520).

Almost surely, 2^6621540 is an apocalyptic number.

6621540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6621540 is an abundant number, since it is smaller than the sum of its proper divisors (11918940).

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

6621540 is a wasteful number, since it uses less digits than its factorization.

6621540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110371 (or 110369 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 6621540 is about 2573.2353176497. The cubic root of 6621540 is about 187.7815857942.

Adding to 6621540 its product of nonzero digits (1440), we get a triangular number (6622980 = T₃₆₃₉).

The spelling of 6621540 in words is "six million, six hundred twenty-one thousand, five hundred forty".