5721556021 has 2 divisors, whose sum is σ = 5721556022. Its totient is φ = 5721556020.

The previous prime is 5721556019. The next prime is 5721556031. The reversal of 5721556021 is 1206551275.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5352531921 + 369024100 = 73161^2 + 19210^2 .

It is a cyclic number.

It is not a de Polignac number, because 5721556021 - 2¹ = 5721556019 is a prime.

Together with 5721556019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5721556031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2860778010 + 2860778011.

It is an arithmetic number, because the mean of its divisors is an integer number (2860778011).

Almost surely, 2^5721556021 is an apocalyptic number.

It is an amenable number.

5721556021 is a deficient number, since it is larger than the sum of its proper divisors (1).

5721556021 is an equidigital number, since it uses as much as digits as its factorization.

5721556021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21000, while the sum is 34.

The square root of 5721556021 is about 75640.9678745586. The cubic root of 5721556021 is about 1788.5649600305.

The spelling of 5721556021 in words is "five billion, seven hundred twenty-one million, five hundred fifty-six thousand, twenty-one".