2521037721 has 4 divisors (see below), whose sum is σ = 3361383632. Its totient is φ = 1680691812.

The previous prime is 2521037693. The next prime is 2521037741. The reversal of 2521037721 is 1277301252.

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 not a de Polignac number, because 2521037721 - 2¹⁰ = 2521036697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2521037741) 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, 420172951 + ... + 420172956.

It is an arithmetic number, because the mean of its divisors is an integer number (840345908).

Almost surely, 2^2521037721 is an apocalyptic number.

It is an amenable number.

2521037721 is a deficient number, since it is larger than the sum of its proper divisors (840345911).

2521037721 is an equidigital number, since it uses as much as digits as its factorization.

2521037721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840345910.

The product of its (nonzero) digits is 5880, while the sum is 30.

The square root of 2521037721 is about 50209.9364767573. The cubic root of 2521037721 is about 1361.0051898654.

Adding to 2521037721 its reverse (1277301252), we get a palindrome (3798338973).

The spelling of 2521037721 in words is "two billion, five hundred twenty-one million, thirty-seven thousand, seven hundred twenty-one".