21106506201601 has 2 divisors, whose sum is σ = 21106506201602. Its totient is φ = 21106506201600.

The previous prime is 21106506201523. The next prime is 21106506201611. The reversal of 21106506201601 is 10610260560112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20706322176400 + 400184025201 = 4550420^2 + 632601^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21106506201601 is a prime.

It is not a weakly prime, because it can be changed into another prime (21106506201611) 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, 10553253100800 + 10553253100801.

It is an arithmetic number, because the mean of its divisors is an integer number (10553253100801).

Almost surely, 2^{21106506201601} is an apocalyptic number.

It is an amenable number.

21106506201601 is a deficient number, since it is larger than the sum of its proper divisors (1).

21106506201601 is an equidigital number, since it uses as much as digits as its factorization.

21106506201601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

Adding to 21106506201601 its reverse (10610260560112), we get a palindrome (31716766761713).

The spelling of 21106506201601 in words is "twenty-one trillion, one hundred six billion, five hundred six million, two hundred one thousand, six hundred one".