21211220121001 has 4 divisors (see below), whose sum is σ = 21211247421952. Its totient is φ = 21211192820052.

The previous prime is 21211220120983. The next prime is 21211220121043. The reversal of 21211220121001 is 10012102211212.

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 21211220121001 - 2³⁷ = 21073781167529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21211220121071) 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, 12449865 + ... + 14050678.

It is an arithmetic number, because the mean of its divisors is an integer number (5302811855488).

Almost surely, 2^{21211220121001} is an apocalyptic number.

It is an amenable number.

21211220121001 is a deficient number, since it is larger than the sum of its proper divisors (27300951).

21211220121001 is an equidigital number, since it uses as much as digits as its factorization.

21211220121001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27300950.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21211220121001 its reverse (10012102211212), we get a palindrome (31223322332213).

The spelling of 21211220121001 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty million, one hundred twenty-one thousand, one".