21216020554499 has 2 divisors, whose sum is σ = 21216020554500. Its totient is φ = 21216020554498.

The previous prime is 21216020554427. The next prime is 21216020554529. The reversal of 21216020554499 is 99445502061212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21216020554499 - 2⁸ = 21216020554243 is a prime.

It is not a weakly prime, because it can be changed into another prime (21216020524499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608010277249 + 10608010277250.

It is an arithmetic number, because the mean of its divisors is an integer number (10608010277250).

Almost surely, 2^{21216020554499} is an apocalyptic number.

21216020554499 is a deficient number, since it is larger than the sum of its proper divisors (1).

21216020554499 is an equidigital number, since it uses as much as digits as its factorization.

21216020554499 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1555200, while the sum is 50.

The spelling of 21216020554499 in words is "twenty-one trillion, two hundred sixteen billion, twenty million, five hundred fifty-four thousand, four hundred ninety-nine".