20021210123 has 4 divisors (see below), whose sum is σ = 20022231528. Its totient is φ = 20020188720.

The previous prime is 20021210087. The next prime is 20021210147. The reversal of 20021210123 is 32101212002.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20021210123 - 2⁶ = 20021210059 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021210098 and 20021210107.

It is not an unprimeable number, because it can be changed into a prime (20021210723) 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 3 ways as a sum of consecutive naturals, for example, 480713 + ... + 520698.

It is an arithmetic number, because the mean of its divisors is an integer number (5005557882).

Almost surely, 2^20021210123 is an apocalyptic number.

20021210123 is a deficient number, since it is larger than the sum of its proper divisors (1021405).

20021210123 is a wasteful number, since it uses less digits than its factorization.

20021210123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1021404.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 20021210123 its reverse (32101212002), we get a palindrome (52122422125).

The spelling of 20021210123 in words is "twenty billion, twenty-one million, two hundred ten thousand, one hundred twenty-three".