6921540 has 36 divisors (see below), whose sum is σ = 20995884. Its totient is φ = 1845696.

The previous prime is 6921527. The next prime is 6921547. The reversal of 6921540 is 451296.

It can be written as a sum of positive squares in 2 ways, for example, as 3048516 + 3873024 = 1746^2 + 1968^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (6921547) 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 11 ways as a sum of consecutive naturals, for example, 19047 + ... + 19406.

It is an arithmetic number, because the mean of its divisors is an integer number (583219).

Almost surely, 2^6921540 is an apocalyptic number.

6921540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6921540 is an abundant number, since it is smaller than the sum of its proper divisors (14074344).

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

6921540 is a wasteful number, since it uses less digits than its factorization.

6921540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38468 (or 38463 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 6921540 is about 2630.8819813895. The cubic root of 6921540 is about 190.5757237140.

It can be divided in two parts, 69 and 21540, that added together give a square (21609 = 147²).

The spelling of 6921540 in words is "six million, nine hundred twenty-one thousand, five hundred forty".