20100121011 has 6 divisors (see below), whose sum is σ = 29033508140. Its totient is φ = 13400080668.

The previous prime is 20100120991. The next prime is 20100121021. The reversal of 20100121011 is 11012100102.

It is a happy number.

It is not a de Polignac number, because 20100121011 - 2⁶ = 20100120947 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: 2233346779 = 20100121011 / (2 + 0 + 1 + 0 + 0 + 1 + 2 + 1 + 0 + 1 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20100120984 and 20100121002.

It is not an unprimeable number, because it can be changed into a prime (20100121021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1116673381 + ... + 1116673398.

Almost surely, 2^20100121011 is an apocalyptic number.

20100121011 is a deficient number, since it is larger than the sum of its proper divisors (8933387129).

20100121011 is a wasteful number, since it uses less digits than its factorization.

20100121011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2233346785 (or 2233346782 counting only the distinct ones).

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

Adding to 20100121011 its reverse (11012100102), we get a palindrome (31112221113).

The spelling of 20100121011 in words is "twenty billion, one hundred million, one hundred twenty-one thousand, eleven".