21121101601 has 2 divisors, whose sum is σ = 21121101602. Its totient is φ = 21121101600.

The previous prime is 21121101593. The next prime is 21121101647. The reversal of 21121101601 is 10610112112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13759290000 + 7361811601 = 117300^2 + 85801^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121101601 - 2³ = 21121101593 is a prime.

It is a super-2 number, since 2×21121101601² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121111601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560550800 + 10560550801.

It is an arithmetic number, because the mean of its divisors is an integer number (10560550801).

Almost surely, 2^21121101601 is an apocalyptic number.

It is an amenable number.

21121101601 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121101601 is an equidigital number, since it uses as much as digits as its factorization.

21121101601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 16.

Adding to 21121101601 its reverse (10610112112), we get a palindrome (31731213713).

The spelling of 21121101601 in words is "twenty-one billion, one hundred twenty-one million, one hundred one thousand, six hundred one".