20111221001 has 4 divisors (see below), whose sum is σ = 20264741904. Its totient is φ = 19957700100.

The previous prime is 20111220937. The next prime is 20111221003. The reversal of 20111221001 is 10012211102.

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 20111221001 - 2⁶ = 20111220937 is a prime.

It is a super-2 number, since 2×20111221001² (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 (20111221003) 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, 76760255 + ... + 76760516.

It is an arithmetic number, because the mean of its divisors is an integer number (5066185476).

Almost surely, 2^20111221001 is an apocalyptic number.

It is an amenable number.

20111221001 is a deficient number, since it is larger than the sum of its proper divisors (153520903).

20111221001 is a wasteful number, since it uses less digits than its factorization.

20111221001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153520902.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 20111221001 its reverse (10012211102), we get a palindrome (30123432103).

The spelling of 20111221001 in words is "twenty billion, one hundred eleven million, two hundred twenty-one thousand, one".