2021721571 has 2 divisors, whose sum is σ = 2021721572. Its totient is φ = 2021721570.

The previous prime is 2021721563. The next prime is 2021721587. The reversal of 2021721571 is 1751271202.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2021721571 - 2³ = 2021721563 is a prime.

It is a super-2 number, since 2×2021721571² = 8174716221293416082, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2021721271) 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, 1010860785 + 1010860786.

It is an arithmetic number, because the mean of its divisors is an integer number (1010860786).

Almost surely, 2^2021721571 is an apocalyptic number.

2021721571 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021721571 is an equidigital number, since it uses as much as digits as its factorization.

2021721571 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1960, while the sum is 28.

The square root of 2021721571 is about 44963.5582555473. The cubic root of 2021721571 is about 1264.4658800062.

Adding to 2021721571 its reverse (1751271202), we get a palindrome (3772992773).

The spelling of 2021721571 in words is "two billion, twenty-one million, seven hundred twenty-one thousand, five hundred seventy-one".