2520638821 has 4 divisors (see below), whose sum is σ = 2523318444. Its totient is φ = 2517959200.

The previous prime is 2520638789. The next prime is 2520638851. The reversal of 2520638821 is 1288360252.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 598780900 + 1921857921 = 24470^2 + 43839^2 .

It is a cyclic number.

It is not a de Polignac number, because 2520638821 - 2⁵ = 2520638789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2520638851) 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, 1338400 + ... + 1340281.

It is an arithmetic number, because the mean of its divisors is an integer number (630829611).

Almost surely, 2^2520638821 is an apocalyptic number.

It is an amenable number.

2520638821 is a deficient number, since it is larger than the sum of its proper divisors (2679623).

2520638821 is an equidigital number, since it uses as much as digits as its factorization.

2520638821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2679622.

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 2520638821 is about 50205.9639983140. The cubic root of 2520638821 is about 1360.9334028122.

The spelling of 2520638821 in words is "two billion, five hundred twenty million, six hundred thirty-eight thousand, eight hundred twenty-one".