20111111001 has 10 divisors (see below), whose sum is σ = 30042523962. Its totient is φ = 13407407280.

The previous prime is 20111110997. The next prime is 20111111003. The reversal of 20111111001 is 10011111102.

It can be written as a sum of positive squares in only one way, i.e., 12984374601 + 7126736400 = 113949^2 + 84420^2 .

It is not a de Polignac number, because 20111111001 - 2² = 20111110997 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (20111111003) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 124142580 + ... + 124142741.

Almost surely, 2^20111111001 is an apocalyptic number.

It is an amenable number.

20111111001 is a deficient number, since it is larger than the sum of its proper divisors (9931412961).

20111111001 is an equidigital number, since it uses as much as digits as its factorization.

20111111001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248285333 (or 248285324 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 20111111001 its reverse (10011111102), we get a palindrome (30122222103).

The spelling of 20111111001 in words is "twenty billion, one hundred eleven million, one hundred eleven thousand, one".