21001221022101 has 4 divisors (see below), whose sum is σ = 28001628029472. Its totient is φ = 14000814014732.

The previous prime is 21001221022039. The next prime is 21001221022127. The reversal of 21001221022101 is 10122012210012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21001221022101 - 2¹¹ = 21001221020053 is a prime.

It is a super-2 number, since 2×21001221022101² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001221021101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3500203503681 + ... + 3500203503686.

It is an arithmetic number, because the mean of its divisors is an integer number (7000407007368).

Almost surely, 2^{21001221022101} is an apocalyptic number.

It is an amenable number.

21001221022101 is a deficient number, since it is larger than the sum of its proper divisors (7000407007371).

21001221022101 is an equidigital number, since it uses as much as digits as its factorization.

21001221022101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7000407007370.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21001221022101 its reverse (10122012210012), we get a palindrome (31123233232113).

The spelling of 21001221022101 in words is "twenty-one trillion, one billion, two hundred twenty-one million, twenty-two thousand, one hundred one".