20011121021 has 4 divisors (see below), whose sum is σ = 20022499200. Its totient is φ = 19999742844.

The previous prime is 20011121017. The next prime is 20011121057. The reversal of 20011121021 is 12012111002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20011121021 - 2² = 20011121017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20011120993 and 20011121011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20011120021) 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, 5686451 + ... + 5689968.

It is an arithmetic number, because the mean of its divisors is an integer number (5005624800).

Almost surely, 2^20011121021 is an apocalyptic number.

It is an amenable number.

20011121021 is a deficient number, since it is larger than the sum of its proper divisors (11378179).

20011121021 is a wasteful number, since it uses less digits than its factorization.

20011121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11378178.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 20011121021 its reverse (12012111002), we get a palindrome (32023232023).

The spelling of 20011121021 in words is "twenty billion, eleven million, one hundred twenty-one thousand, twenty-one".