21324401421 has 16 divisors (see below), whose sum is σ = 28761222336. Its totient is φ = 14052600576.

The previous prime is 21324401393. The next prime is 21324401429. The reversal of 21324401421 is 12410442312.

It is not a de Polignac number, because 21324401421 - 2¹³ = 21324393229 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21324401391 and 21324401400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21324401429) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42126 + ... + 210768.

It is an arithmetic number, because the mean of its divisors is an integer number (1797576396).

Almost surely, 2^21324401421 is an apocalyptic number.

It is an amenable number.

21324401421 is a deficient number, since it is larger than the sum of its proper divisors (7436820915).

21324401421 is a wasteful number, since it uses less digits than its factorization.

21324401421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169132.

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21324401421 its reverse (12410442312), we get a palindrome (33734843733).

The spelling of 21324401421 in words is "twenty-one billion, three hundred twenty-four million, four hundred one thousand, four hundred twenty-one".