2521640 has 48 divisors (see below), whose sum is σ = 6248340. Its totient is φ = 915200.

The previous prime is 2521621. The next prime is 2521643. The reversal of 2521640 is 461252.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2439844 + 81796 = 1562^2 + 286^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (2521643) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4580 + ... + 5100.

2^2521640 is an apocalyptic number.

2521640 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 2521640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3124170).

2521640 is an abundant number, since it is smaller than the sum of its proper divisors (3726700).

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

2521640 is a wasteful number, since it uses less digits than its factorization.

2521640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554 (or 539 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 2521640 is about 1587.9672540704. The cubic root of 2521640 is about 136.1113563171. Note that the first 3 decimals are identical.

Adding to 2521640 its reverse (461252), we get a palindrome (2982892).

The spelling of 2521640 in words is "two million, five hundred twenty-one thousand, six hundred forty".