21516151120447 has 2 divisors, whose sum is σ = 21516151120448. Its totient is φ = 21516151120446.

The previous prime is 21516151120351. The next prime is 21516151120459. The reversal of 21516151120447 is 74402115161512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21516151120447 - 2¹⁹ = 21516150596159 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21516151127447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10758075560223 + 10758075560224.

It is an arithmetic number, because the mean of its divisors is an integer number (10758075560224).

Almost surely, 2^{21516151120447} is an apocalyptic number.

21516151120447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21516151120447 is an equidigital number, since it uses as much as digits as its factorization.

21516151120447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 67200, while the sum is 40.

Adding to 21516151120447 its reverse (74402115161512), we get a palindrome (95918266281959).

The spelling of 21516151120447 in words is "twenty-one trillion, five hundred sixteen billion, one hundred fifty-one million, one hundred twenty thousand, four hundred forty-seven".