6640920 has 256 divisors, whose sum is σ = 26611200. Its totient is φ = 1451520.

The previous prime is 6640903. The next prime is 6640927. The reversal of 6640920 is 290466.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640927) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 154419 + ... + 154461.

It is an arithmetic number, because the mean of its divisors is an integer number (103950).

Almost surely, 2^6640920 is an apocalyptic number.

6640920 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 6640920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13305600).

6640920 is an abundant number, since it is smaller than the sum of its proper divisors (19970280).

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

6640920 is a wasteful number, since it uses less digits than its factorization.

6640920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 6640920 is about 2576.9982537829. The cubic root of 6640920 is about 187.9646077936.

The spelling of 6640920 in words is "six million, six hundred forty thousand, nine hundred twenty".