21101220001 has 2 divisors, whose sum is σ = 21101220002. Its totient is φ = 21101220000.

The previous prime is 21101219987. The next prime is 21101220017. The reversal of 21101220001 is 10002210112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20152641600 + 948578401 = 141960^2 + 30799^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101220001 - 2¹¹ = 21101217953 is a prime.

It is a super-2 number, since 2×21101220001² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21101220001.

It is not a weakly prime, because it can be changed into another prime (21101220401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550610000 + 10550610001.

It is an arithmetic number, because the mean of its divisors is an integer number (10550610001).

Almost surely, 2^21101220001 is an apocalyptic number.

It is an amenable number.

21101220001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101220001 is an equidigital number, since it uses as much as digits as its factorization.

21101220001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21101220001 its reverse (10002210112), we get a palindrome (31103430113).

The spelling of 21101220001 in words is "twenty-one billion, one hundred one million, two hundred twenty thousand, one".