21216020143121 has 2 divisors, whose sum is σ = 21216020143122. Its totient is φ = 21216020143120.

The previous prime is 21216020143069. The next prime is 21216020143133. The reversal of 21216020143121 is 12134102061212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11677255840000 + 9538764303121 = 3417200^2 + 3088489^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21216020143121 is a prime.

It is not a weakly prime, because it can be changed into another prime (21216020143921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608010071560 + 10608010071561.

It is an arithmetic number, because the mean of its divisors is an integer number (10608010071561).

Almost surely, 2^{21216020143121} is an apocalyptic number.

It is an amenable number.

21216020143121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21216020143121 is an equidigital number, since it uses as much as digits as its factorization.

21216020143121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 26.

The spelling of 21216020143121 in words is "twenty-one trillion, two hundred sixteen billion, twenty million, one hundred forty-three thousand, one hundred twenty-one".