20111221201 has 4 divisors (see below), whose sum is σ = 20759970304. Its totient is φ = 19462472100.

The previous prime is 20111221199. The next prime is 20111221219. The reversal of 20111221201 is 10212211102.

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, and also an emirpimes, since its reverse is a distinct semiprime: 10212211102 = 2 ⋅5106105551.

It is a cyclic number.

It is not a de Polignac number, because 20111221201 - 2¹ = 20111221199 is a prime.

It is a super-2 number, since 2×20111221201² (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 (20111221241) 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, 324374505 + ... + 324374566.

It is an arithmetic number, because the mean of its divisors is an integer number (5189992576).

Almost surely, 2^20111221201 is an apocalyptic number.

It is an amenable number.

20111221201 is a deficient number, since it is larger than the sum of its proper divisors (648749103).

20111221201 is an equidigital number, since it uses as much as digits as its factorization.

20111221201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648749102.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 20111221201 its reverse (10212211102), we get a palindrome (30323432303).

The spelling of 20111221201 in words is "twenty billion, one hundred eleven million, two hundred twenty-one thousand, two hundred one".