20000231021 has 4 divisors (see below), whose sum is σ = 20004698844.
Its totient is φ = 19995763200.
The previous prime is 20000230981. The next prime is 20000231039. The reversal of 20000231021 is 12013200002.
It is a happy number.
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 11504922121 + 8495308900 = 107261^2 + 92170^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-20000231021 is a prime.
It is a Duffinian number.
It is a Curzon number.
It is a junction number, because it is equal to n+sod(n) for n = 20000230993 and 20000231011.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20000231071) 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, 2227190 + ... + 2236151.
It is an arithmetic number, because the mean of its divisors is an integer number (5001174711).
Almost surely, 220000231021 is an apocalyptic number.
It is an amenable number.
20000231021 is a deficient number, since it is larger than the sum of its proper divisors (4467823).
20000231021 is an equidigital number, since it uses as much as digits as its factorization.
20000231021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 4467822.
The product of its (nonzero) digits is 24, while the sum is 11.
Adding to 20000231021 its reverse (12013200002), we get a palindrome (32013431023).
The spelling of 20000231021 in words is "twenty billion, two hundred thirty-one thousand, twenty-one".