20010021121 has 4 divisors (see below), whose sum is σ = 20208140244. Its totient is φ = 19811902000.

The previous prime is 20010021103. The next prime is 20010021131. The reversal of 20010021121 is 12112001002.

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 16786052721 + 3223968400 = 129561^2 + 56780^2 .

It is a cyclic number.

It is not a de Polignac number, because 20010021121 - 2⁵ = 20010021089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20010021098 and 20010021107.

It is not an unprimeable number, because it can be changed into a prime (20010021131) 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, 99059410 + ... + 99059611.

It is an arithmetic number, because the mean of its divisors is an integer number (5052035061).

Almost surely, 2^20010021121 is an apocalyptic number.

It is an amenable number.

20010021121 is a deficient number, since it is larger than the sum of its proper divisors (198119123).

20010021121 is a wasteful number, since it uses less digits than its factorization.

20010021121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198119122.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 20010021121 its reverse (12112001002), we get a palindrome (32122022123).

The spelling of 20010021121 in words is "twenty billion, ten million, twenty-one thousand, one hundred twenty-one".