21424214021 has 4 divisors (see below), whose sum is σ = 24484816032. Its totient is φ = 18363612012.

The previous prime is 21424213999. The next prime is 21424214039. The reversal of 21424214021 is 12041242412.

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 21424214021 - 2²⁶ = 21357105157 is a prime.

It is a super-2 number, since 2×21424214021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424210021) 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, 1530300995 + ... + 1530301008.

It is an arithmetic number, because the mean of its divisors is an integer number (6121204008).

Almost surely, 2^21424214021 is an apocalyptic number.

It is an amenable number.

21424214021 is a deficient number, since it is larger than the sum of its proper divisors (3060602011).

21424214021 is an equidigital number, since it uses as much as digits as its factorization.

21424214021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3060602010.

The product of its (nonzero) digits is 1024, while the sum is 23.

Adding to 21424214021 its reverse (12041242412), we get a palindrome (33465456433).

The spelling of 21424214021 in words is "twenty-one billion, four hundred twenty-four million, two hundred fourteen thousand, twenty-one".