20211309421 has 2 divisors, whose sum is σ = 20211309422. Its totient is φ = 20211309420.

The previous prime is 20211309389. The next prime is 20211309473. The reversal of 20211309421 is 12490311202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11904992100 + 8306317321 = 109110^2 + 91139^2 .

It is a cyclic number.

It is not a de Polignac number, because 20211309421 - 2⁵ = 20211309389 is a prime.

It is a super-2 number, since 2×20211309421² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20211307421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105654710 + 10105654711.

It is an arithmetic number, because the mean of its divisors is an integer number (10105654711).

Almost surely, 2^20211309421 is an apocalyptic number.

It is an amenable number.

20211309421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20211309421 is an equidigital number, since it uses as much as digits as its factorization.

20211309421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The spelling of 20211309421 in words is "twenty billion, two hundred eleven million, three hundred nine thousand, four hundred twenty-one".