2520756721 has 4 divisors (see below), whose sum is σ = 2880864832. Its totient is φ = 2160648612.

The previous prime is 2520756709. The next prime is 2520756731. The reversal of 2520756721 is 1276570252.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2520756721 - 2¹⁹ = 2520232433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2520756731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 180054045 + ... + 180054058.

It is an arithmetic number, because the mean of its divisors is an integer number (720216208).

Almost surely, 2^2520756721 is an apocalyptic number.

It is an amenable number.

2520756721 is a deficient number, since it is larger than the sum of its proper divisors (360108111).

2520756721 is an equidigital number, since it uses as much as digits as its factorization.

2520756721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360108110.

The product of its (nonzero) digits is 58800, while the sum is 37.

The square root of 2520756721 is about 50207.1381478769. The cubic root of 2520756721 is about 1360.9546211829.

The spelling of 2520756721 in words is "two billion, five hundred twenty million, seven hundred fifty-six thousand, seven hundred twenty-one".