6499840 has 40 divisors (see below), whose sum is σ = 15590520. Its totient is φ = 2598912.

The previous prime is 6499793. The next prime is 6499841. The reversal of 6499840 is 489946.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 6499793 and 6499802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6499841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1291 + ... + 3829.

It is an arithmetic number, because the mean of its divisors is an integer number (389763).

Almost surely, 2^6499840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6499840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7795260).

6499840 is an abundant number, since it is smaller than the sum of its proper divisors (9090680).

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

6499840 is an equidigital number, since it uses as much as digits as its factorization.

6499840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2562 (or 2546 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 6499840 is about 2549.4783780217. The cubic root of 6499840 is about 186.6240265417.

The spelling of 6499840 in words is "six million, four hundred ninety-nine thousand, eight hundred forty".