20266721 has 2 divisors, whose sum is σ = 20266722. Its totient is φ = 20266720.

The previous prime is 20266709. The next prime is 20266733. The reversal of 20266721 is 12766202.

It is a balanced prime because it is at equal distance from previous prime (20266709) and next prime (20266733).

It can be written as a sum of positive squares in only one way, i.e., 20151121 + 115600 = 4489^2 + 340^2 .

It is a cyclic number.

It is not a de Polignac number, because 20266721 - 2¹⁰ = 20265697 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20269721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10133360 + 10133361.

It is an arithmetic number, because the mean of its divisors is an integer number (10133361).

Almost surely, 2^20266721 is an apocalyptic number.

It is an amenable number.

20266721 is a deficient number, since it is larger than the sum of its proper divisors (1).

20266721 is an equidigital number, since it uses as much as digits as its factorization.

20266721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 20266721 is about 4501.8575055192. The cubic root of 20266721 is about 272.6430906884.

The spelling of 20266721 in words is "twenty million, two hundred sixty-six thousand, seven hundred twenty-one".