2640820 has 48 divisors (see below), whose sum is σ = 6830208. Its totient is φ = 835200.

The previous prime is 2640779. The next prime is 2640821. The reversal of 2640820 is 280462.

It is a junction number, because it is equal to n+sod(n) for n = 2640791 and 2640800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2640821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1095 + ... + 2545.

It is an arithmetic number, because the mean of its divisors is an integer number (142296).

2^2640820 is an apocalyptic number.

2640820 is a gapful number since it is divisible by the number (20) 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 2640820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3415104).

2640820 is an abundant number, since it is smaller than the sum of its proper divisors (4189388).

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

2640820 is a wasteful number, since it uses less digits than its factorization.

2640820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1480 (or 1478 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 2640820 is about 1625.0599988923. The cubic root of 2640820 is about 138.2227725812. Note that the first 3 decimals are identical.

The spelling of 2640820 in words is "two million, six hundred forty thousand, eight hundred twenty".