21020430021 has 8 divisors (see below), whose sum is σ = 28028514624. Its totient is φ = 14012982720.

The previous prime is 21020430007. The next prime is 21020430049. The reversal of 21020430021 is 12003402012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21020430021 - 2²⁵ = 20986875589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020435021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76161 + ... + 218726.

It is an arithmetic number, because the mean of its divisors is an integer number (3503564328).

Almost surely, 2^21020430021 is an apocalyptic number.

It is an amenable number.

21020430021 is a deficient number, since it is larger than the sum of its proper divisors (7008084603).

21020430021 is a wasteful number, since it uses less digits than its factorization.

21020430021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318651.

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 21020430021 its reverse (12003402012), we get a palindrome (33023832033).

The spelling of 21020430021 in words is "twenty-one billion, twenty million, four hundred thirty thousand, twenty-one".