21121220201 has 4 divisors (see below), whose sum is σ = 21121682304. Its totient is φ = 21120758100.

The previous prime is 21121220177. The next prime is 21121220227. The reversal of 21121220201 is 10202212112.

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 21121220201 - 2¹⁸ = 21120958057 is a prime.

It is a super-2 number, since 2×21121220201² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121229201) 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, 153905 + ... + 256766.

It is an arithmetic number, because the mean of its divisors is an integer number (5280420576).

Almost surely, 2^21121220201 is an apocalyptic number.

It is an amenable number.

21121220201 is a deficient number, since it is larger than the sum of its proper divisors (462103).

21121220201 is an equidigital number, since it uses as much as digits as its factorization.

21121220201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 462102.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21121220201 its reverse (10202212112), we get a palindrome (31323432313).

The spelling of 21121220201 in words is "twenty-one billion, one hundred twenty-one million, two hundred twenty thousand, two hundred one".