21161004001421 has 2 divisors, whose sum is σ = 21161004001422. Its totient is φ = 21161004001420.

The previous prime is 21161004001411. The next prime is 21161004001453. The reversal of 21161004001421 is 12410040016112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20454941925796 + 706062075625 = 4522714^2 + 840275^2 .

It is a cyclic number.

It is not a de Polignac number, because 21161004001421 - 2¹⁰ = 21161004000397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21161004001411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10580502000710 + 10580502000711.

It is an arithmetic number, because the mean of its divisors is an integer number (10580502000711).

Almost surely, 2^{21161004001421} is an apocalyptic number.

It is an amenable number.

21161004001421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21161004001421 is an equidigital number, since it uses as much as digits as its factorization.

21161004001421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 23.

Adding to 21161004001421 its reverse (12410040016112), we get a palindrome (33571044017533).

The spelling of 21161004001421 in words is "twenty-one trillion, one hundred sixty-one billion, four million, one thousand, four hundred twenty-one".