21001211212201 has 4 divisors (see below), whose sum is σ = 22910412231504. Its totient is φ = 19092010192900.

The previous prime is 21001211212187. The next prime is 21001211212279. The reversal of 21001211212201 is 10221211210012.

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 21001211212201 - 2¹⁹ = 21001210687913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001211212001) 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, 954600509635 + ... + 954600509656.

It is an arithmetic number, because the mean of its divisors is an integer number (5727603057876).

Almost surely, 2^{21001211212201} is an apocalyptic number.

It is an amenable number.

21001211212201 is a deficient number, since it is larger than the sum of its proper divisors (1909201019303).

21001211212201 is a wasteful number, since it uses less digits than its factorization.

21001211212201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1909201019302.

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

Adding to 21001211212201 its reverse (10221211210012), we get a palindrome (31222422422213).

The spelling of 21001211212201 in words is "twenty-one trillion, one billion, two hundred eleven million, two hundred twelve thousand, two hundred one".