20210231021 has 4 divisors (see below), whose sum is σ = 20223878844. Its totient is φ = 20196583200.

The previous prime is 20210230991. The next prime is 20210231033. The reversal of 20210231021 is 12013201202.

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 6156128521 + 14054102500 = 78461^2 + 118550^2 .

It is a cyclic number.

It is not a de Polignac number, because 20210231021 - 2²² = 20206036717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20210230987 and 20210231005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20210231221) 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, 6821690 + ... + 6824651.

It is an arithmetic number, because the mean of its divisors is an integer number (5055969711).

Almost surely, 2^20210231021 is an apocalyptic number.

It is an amenable number.

20210231021 is a deficient number, since it is larger than the sum of its proper divisors (13647823).

20210231021 is a wasteful number, since it uses less digits than its factorization.

20210231021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13647822.

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

Adding to 20210231021 its reverse (12013201202), we get a palindrome (32223432223).

The spelling of 20210231021 in words is "twenty billion, two hundred ten million, two hundred thirty-one thousand, twenty-one".