21375148021 has 2 divisors, whose sum is σ = 21375148022. Its totient is φ = 21375148020.

The previous prime is 21375147979. The next prime is 21375148057. The reversal of 21375148021 is 12084157312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14104175121 + 7270972900 = 118761^2 + 85270^2 .

It is a cyclic number.

It is not a de Polignac number, because 21375148021 - 2¹⁵ = 21375115253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21375148061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10687574010 + 10687574011.

It is an arithmetic number, because the mean of its divisors is an integer number (10687574011).

Almost surely, 2^21375148021 is an apocalyptic number.

It is an amenable number.

21375148021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21375148021 is an equidigital number, since it uses as much as digits as its factorization.

21375148021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13440, while the sum is 34.

The spelling of 21375148021 in words is "twenty-one billion, three hundred seventy-five million, one hundred forty-eight thousand, twenty-one".