20011100121 has 6 divisors (see below), whose sum is σ = 28904922410. Its totient is φ = 13340733408.

The previous prime is 20011100077. The next prime is 20011100141. The reversal of 20011100121 is 12100111002.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19722270096 + 288830025 = 140436^2 + 16995^2 .

It is not a de Polignac number, because 20011100121 - 2⁹ = 20011099609 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 2223455569 = 20011100121 / (2 + 0 + 0 + 1 + 1 + 1 + 0 + 0 + 1 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20011100141) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1111727776 + ... + 1111727793.

Almost surely, 2^20011100121 is an apocalyptic number.

It is an amenable number.

20011100121 is a deficient number, since it is larger than the sum of its proper divisors (8893822289).

20011100121 is a wasteful number, since it uses less digits than its factorization.

20011100121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2223455575 (or 2223455572 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 20011100121 its reverse (12100111002), we get a palindrome (32111211123).

The spelling of 20011100121 in words is "twenty billion, eleven million, one hundred thousand, one hundred twenty-one".