20100121001 has 4 divisors (see below), whose sum is σ = 20277998292. Its totient is φ = 19922243712.

The previous prime is 20100120991. The next prime is 20100121021. The reversal of 20100121001 is 10012100102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5749278976 + 14350842025 = 75824^2 + 119795^2 .

It is a cyclic number.

It is not a de Polignac number, because 20100121001 - 2²⁶ = 20033012137 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20100121001.

It is not an unprimeable number, because it can be changed into a prime (20100121021) 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, 88938476 + ... + 88938701.

It is an arithmetic number, because the mean of its divisors is an integer number (5069499573).

Almost surely, 2^20100121001 is an apocalyptic number.

It is an amenable number.

20100121001 is a deficient number, since it is larger than the sum of its proper divisors (177877291).

20100121001 is a wasteful number, since it uses less digits than its factorization.

20100121001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177877290.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 20100121001 its reverse (10012100102), we get a palindrome (30112221103).

The spelling of 20100121001 in words is "twenty billion, one hundred million, one hundred twenty-one thousand, one".