21010430021 has 4 divisors (see below), whose sum is σ = 24011920032. Its totient is φ = 18008940012.

The previous prime is 21010430009. The next prime is 21010430059. The reversal of 21010430021 is 12003401012.

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 not a de Polignac number, because 21010430021 - 2¹⁰ = 21010428997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010429978 and 21010430005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010432021) 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, 1500744995 + ... + 1500745008.

It is an arithmetic number, because the mean of its divisors is an integer number (6002980008).

Almost surely, 2^21010430021 is an apocalyptic number.

It is an amenable number.

21010430021 is a deficient number, since it is larger than the sum of its proper divisors (3001490011).

21010430021 is an equidigital number, since it uses as much as digits as its factorization.

21010430021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3001490010.

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

Adding to 21010430021 its reverse (12003401012), we get a palindrome (33013831033).

The spelling of 21010430021 in words is "twenty-one billion, ten million, four hundred thirty thousand, twenty-one".