21433030021 has 4 divisors (see below), whose sum is σ = 23081724652. Its totient is φ = 19784335392.

The previous prime is 21433030019. The next prime is 21433030043. The reversal of 21433030021 is 12003033412.

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 14789964996 + 6643065025 = 121614^2 + 81505^2 .

It is a cyclic number.

It is not a de Polignac number, because 21433030021 - 2¹ = 21433030019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21433030121) 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, 824347296 + ... + 824347321.

It is an arithmetic number, because the mean of its divisors is an integer number (5770431163).

Almost surely, 2^21433030021 is an apocalyptic number.

It is an amenable number.

21433030021 is a deficient number, since it is larger than the sum of its proper divisors (1648694631).

21433030021 is a wasteful number, since it uses less digits than its factorization.

21433030021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1648694630.

The product of its (nonzero) digits is 432, while the sum is 19.

Adding to 21433030021 its reverse (12003033412), we get a palindrome (33436063433).

The spelling of 21433030021 in words is "twenty-one billion, four hundred thirty-three million, thirty thousand, twenty-one".