21001201201111 has 2 divisors, whose sum is σ = 21001201201112. Its totient is φ = 21001201201110.

The previous prime is 21001201201103. The next prime is 21001201201139. The reversal of 21001201201111 is 11110210210012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21001201201111 - 2³ = 21001201201103 is a prime.

It is a super-2 number, since 2×21001201201111² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21001201201091 and 21001201201100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001201201411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500600600555 + 10500600600556.

It is an arithmetic number, because the mean of its divisors is an integer number (10500600600556).

Almost surely, 2^{21001201201111} is an apocalyptic number.

21001201201111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001201201111 is an equidigital number, since it uses as much as digits as its factorization.

21001201201111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21001201201111 its reverse (11110210210012), we get a palindrome (32111411411123).

The spelling of 21001201201111 in words is "twenty-one trillion, one billion, two hundred one million, two hundred one thousand, one hundred eleven".