21001221221147 has 2 divisors, whose sum is σ = 21001221221148. Its totient is φ = 21001221221146.

The previous prime is 21001221221041. The next prime is 21001221221177. The reversal of 21001221221147 is 74112212210012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001221221147 - 2¹² = 21001221217051 is a prime.

It is not a weakly prime, because it can be changed into another prime (21001221221177) 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, 10500610610573 + 10500610610574.

It is an arithmetic number, because the mean of its divisors is an integer number (10500610610574).

Almost surely, 2^{21001221221147} is an apocalyptic number.

21001221221147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001221221147 is an equidigital number, since it uses as much as digits as its factorization.

21001221221147 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 26.

Adding to 21001221221147 its reverse (74112212210012), we get a palindrome (95113433431159).

The spelling of 21001221221147 in words is "twenty-one trillion, one billion, two hundred twenty-one million, two hundred twenty-one thousand, one hundred forty-seven".