21323424021 has 16 divisors (see below), whose sum is σ = 28523025600. Its totient is φ = 14169772800.

The previous prime is 21323424013. The next prime is 21323424029. The reversal of 21323424021 is 12042432312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21323424013) and next prime (21323424029).

It is not a de Polignac number, because 21323424021 - 2³ = 21323424013 is a prime.

It is a super-3 number, since 3×21323424021³ (a number of 32 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21323423982 and 21323424000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323424029) 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 15 ways as a sum of consecutive naturals, for example, 1857726 + ... + 1869168.

It is an arithmetic number, because the mean of its divisors is an integer number (1782689100).

Almost surely, 2^21323424021 is an apocalyptic number.

It is an amenable number.

21323424021 is a deficient number, since it is larger than the sum of its proper divisors (7199601579).

21323424021 is a wasteful number, since it uses less digits than its factorization.

21323424021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13396.

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21323424021 its reverse (12042432312), we get a palindrome (33365856333).

The spelling of 21323424021 in words is "twenty-one billion, three hundred twenty-three million, four hundred twenty-four thousand, twenty-one".