21430030021 has 4 divisors (see below), whose sum is σ = 22121321344. Its totient is φ = 20738738700.

The previous prime is 21430030003. The next prime is 21430030073. The reversal of 21430030021 is 12003003412.

It is a happy number.

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 21430030021 - 2¹⁹ = 21429505733 is a prime.

It is a super-2 number, since 2×21430030021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21430029977 and 21430030004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21430030001) by changing a digit.

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, 345645615 + ... + 345645676.

It is an arithmetic number, because the mean of its divisors is an integer number (5530330336).

Almost surely, 2^21430030021 is an apocalyptic number.

It is an amenable number.

21430030021 is a deficient number, since it is larger than the sum of its proper divisors (691291323).

21430030021 is an equidigital number, since it uses as much as digits as its factorization.

21430030021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 691291322.

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21430030021 its reverse (12003003412), we get a palindrome (33433033433).

It can be divided in two parts, 214300300 and 21, that added together give a square (214300321 = 14639²).

The spelling of 21430030021 in words is "twenty-one billion, four hundred thirty million, thirty thousand, twenty-one".