20421719 has 2 divisors, whose sum is σ = 20421720. Its totient is φ = 20421718.

The previous prime is 20421703. The next prime is 20421733. The reversal of 20421719 is 91712402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20421719 - 2⁴ = 20421703 is a prime.

It is a super-2 number, since 2×20421719² = 834093213829922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20421749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210859 + 10210860.

It is an arithmetic number, because the mean of its divisors is an integer number (10210860).

Almost surely, 2^20421719 is an apocalyptic number.

20421719 is a deficient number, since it is larger than the sum of its proper divisors (1).

20421719 is an equidigital number, since it uses as much as digits as its factorization.

20421719 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 20421719 is about 4519.0396103597. The cubic root of 20421719 is about 273.3363759659.

The spelling of 20421719 in words is "twenty million, four hundred twenty-one thousand, seven hundred nineteen".