2021729 has 2 divisors, whose sum is σ = 2021730. Its totient is φ = 2021728.

The previous prime is 2021711. The next prime is 2021737. The reversal of 2021729 is 9271202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2016400 + 5329 = 1420^2 + 73^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2021729 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2021779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010864 + 1010865.

It is an arithmetic number, because the mean of its divisors is an integer number (1010865).

2^2021729 is an apocalyptic number.

It is an amenable number.

2021729 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021729 is an equidigital number, since it uses as much as digits as its factorization.

2021729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 2021729 is about 1421.8751703297. The cubic root of 2021729 is about 126.4467428803.

The spelling of 2021729 in words is "two million, twenty-one thousand, seven hundred twenty-nine".