21020231005 has 4 divisors (see below), whose sum is σ = 25224277212. Its totient is φ = 16816184800.

The previous prime is 21020230981. The next prime is 21020231027. The reversal of 21020231005 is 50013202012.

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 3939570756 + 17080660249 = 62766^2 + 130693^2 .

It is not a de Polignac number, because 21020231005 - 2²⁵ = 20986676573 is a prime.

It is a super-2 number, since 2×21020231005² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21020231005.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2102023096 + ... + 2102023105.

It is an arithmetic number, because the mean of its divisors is an integer number (6306069303).

Almost surely, 2^21020231005 is an apocalyptic number.

It is an amenable number.

21020231005 is a deficient number, since it is larger than the sum of its proper divisors (4204046207).

21020231005 is an equidigital number, since it uses as much as digits as its factorization.

21020231005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4204046206.

The product of its (nonzero) digits is 120, while the sum is 16.

Adding to 21020231005 its reverse (50013202012), we get a palindrome (71033433017).

The spelling of 21020231005 in words is "twenty-one billion, twenty million, two hundred thirty-one thousand, five".