21051478140221 has 2 divisors, whose sum is σ = 21051478140222. Its totient is φ = 21051478140220.

The previous prime is 21051478140211. The next prime is 21051478140269. The reversal of 21051478140221 is 12204187415012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19720082932900 + 1331395207321 = 4440730^2 + 1153861^2 .

It is a cyclic number.

It is not a de Polignac number, because 21051478140221 - 2¹⁸ = 21051477878077 is a prime.

It is a super-2 number, since 2×21051478140221² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21051478140211) 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, 10525739070110 + 10525739070111.

It is an arithmetic number, because the mean of its divisors is an integer number (10525739070111).

Almost surely, 2^{21051478140221} is an apocalyptic number.

It is an amenable number.

21051478140221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21051478140221 is an equidigital number, since it uses as much as digits as its factorization.

21051478140221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 35840, while the sum is 38.

The spelling of 21051478140221 in words is "twenty-one trillion, fifty-one billion, four hundred seventy-eight million, one hundred forty thousand, two hundred twenty-one".