221001012101021 has 6 divisors (see below), whose sum is σ = 224810279765022. Its totient is φ = 217255232231480.

The previous prime is 221001012100997. The next prime is 221001012101057. The reversal of 221001012101021 is 120101210100122.

It can be written as a sum of positive squares in only one way, i.e., 219262796625625 + 1738215475396 = 14807525^2 + 1318414^2 .

It is a de Polignac number, because none of the positive numbers 2^k-221001012101021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221001012100987 and 221001012101005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221001012101081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 31743893690 + ... + 31743900651.

It is an arithmetic number, because the mean of its divisors is an integer number (37468379960837).

Almost surely, 2^{221001012101021} is an apocalyptic number.

It is an amenable number.

221001012101021 is a deficient number, since it is larger than the sum of its proper divisors (3809267664001).

221001012101021 is an frugal number, since it uses more digits than its factorization.

221001012101021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63487794459 (or 63487794400 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 221001012101021 its reverse (120101210100122), we get a palindrome (341102222201143).

The spelling of 221001012101021 in words is "two hundred twenty-one trillion, one billion, twelve million, one hundred one thousand, twenty-one".