2291721521 has 2 divisors, whose sum is σ = 2291721522. Its totient is φ = 2291721520.

The previous prime is 2291721511. The next prime is 2291721547. The reversal of 2291721521 is 1251271922.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1356890896 + 934830625 = 36836^2 + 30575^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2291721521 is a prime.

It is not a weakly prime, because it can be changed into another prime (2291721511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1145860760 + 1145860761.

It is an arithmetic number, because the mean of its divisors is an integer number (1145860761).

Almost surely, 2^2291721521 is an apocalyptic number.

It is an amenable number.

2291721521 is a deficient number, since it is larger than the sum of its proper divisors (1).

2291721521 is an equidigital number, since it uses as much as digits as its factorization.

2291721521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5040, while the sum is 32.

The square root of 2291721521 is about 47871.9283192144. The cubic root of 2291721521 is about 1318.4205015058.

The spelling of 2291721521 in words is "two billion, two hundred ninety-one million, seven hundred twenty-one thousand, five hundred twenty-one".