6581640 has 64 divisors (see below), whose sum is σ = 21268800. Its totient is φ = 1619712.

The previous prime is 6581633. The next prime is 6581683. The reversal of 6581640 is 461856.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 6581598 and 6581607.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 550 + ... + 3669.

It is an arithmetic number, because the mean of its divisors is an integer number (332325).

Almost surely, 2^6581640 is an apocalyptic number.

6581640 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 6581640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10634400).

6581640 is an abundant number, since it is smaller than the sum of its proper divisors (14687160).

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

6581640 is a wasteful number, since it uses less digits than its factorization.

6581640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4246 (or 4242 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 6581640 is about 2565.4707170420. The cubic root of 6581640 is about 187.4036482734.

It can be divided in two parts, 65816 and 40, that added together give a palindrome (65856).

The spelling of 6581640 in words is "six million, five hundred eighty-one thousand, six hundred forty".