2551336721 has 2 divisors, whose sum is σ = 2551336722. Its totient is φ = 2551336720.

The previous prime is 2551336717. The next prime is 2551336747. The reversal of 2551336721 is 1276331552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2187900625 + 363436096 = 46775^2 + 19064^2 .

It is a cyclic number.

It is not a de Polignac number, because 2551336721 - 2² = 2551336717 is a prime.

It is not a weakly prime, because it can be changed into another prime (2551338721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1275668360 + 1275668361.

It is an arithmetic number, because the mean of its divisors is an integer number (1275668361).

Almost surely, 2^2551336721 is an apocalyptic number.

It is an amenable number.

2551336721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2551336721 is an equidigital number, since it uses as much as digits as its factorization.

2551336721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37800, while the sum is 35.

The square root of 2551336721 is about 50510.7584678749. The cubic root of 2551336721 is about 1366.4358885029.

The spelling of 2551336721 in words is "two billion, five hundred fifty-one million, three hundred thirty-six thousand, seven hundred twenty-one".