6638940 has 144 divisors (see below), whose sum is σ = 25159680. Its totient is φ = 1376640.

The previous prime is 6638911. The next prime is 6638953. The reversal of 6638940 is 498366.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6638895 and 6638904.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13621 + ... + 14099.

It is an arithmetic number, because the mean of its divisors is an integer number (174720).

Almost surely, 2^6638940 is an apocalyptic number.

6638940 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 6638940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12579840).

6638940 is an abundant number, since it is smaller than the sum of its proper divisors (18520740).

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

6638940 is a wasteful number, since it uses less digits than its factorization.

6638940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 512 (or 507 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 6638940 is about 2576.6140572464. The cubic root of 6638940 is about 187.9459252960.

The spelling of 6638940 in words is "six million, six hundred thirty-eight thousand, nine hundred forty".