20110121001 has 24 divisors (see below), whose sum is σ = 30379467456. Its totient is φ = 12794839200.

The previous prime is 20110120993. The next prime is 20110121023. The reversal of 20110121001 is 10012101102.

It is a happy number.

It is not a de Polignac number, because 20110121001 - 2³ = 20110120993 is a prime.

It is a super-2 number, since 2×20110121001² (a number of 21 digits) contains 22 as substring.

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 (20110121081) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17950 + ... + 201351.

It is an arithmetic number, because the mean of its divisors is an integer number (1265811144).

Almost surely, 2^20110121001 is an apocalyptic number.

It is an amenable number.

20110121001 is a deficient number, since it is larger than the sum of its proper divisors (10269346455).

20110121001 is a wasteful number, since it uses less digits than its factorization.

20110121001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219773 (or 219770 counting only the distinct ones).

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

Adding to 20110121001 its reverse (10012101102), we get a palindrome (30122222103).

The spelling of 20110121001 in words is "twenty billion, one hundred ten million, one hundred twenty-one thousand, one".