21020033121 has 4 divisors (see below), whose sum is σ = 28026710832. Its totient is φ = 14013355412.

The previous prime is 21020033033. The next prime is 21020033123. The reversal of 21020033121 is 12133002012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21020033121 - 2¹¹ = 21020031073 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21020033121.

It is not an unprimeable number, because it can be changed into a prime (21020033123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3503338851 + ... + 3503338856.

It is an arithmetic number, because the mean of its divisors is an integer number (7006677708).

Almost surely, 2^21020033121 is an apocalyptic number.

It is an amenable number.

21020033121 is a deficient number, since it is larger than the sum of its proper divisors (7006677711).

21020033121 is an equidigital number, since it uses as much as digits as its factorization.

21020033121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7006677710.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21020033121 its reverse (12133002012), we get a palindrome (33153035133).

The spelling of 21020033121 in words is "twenty-one billion, twenty million, thirty-three thousand, one hundred twenty-one".