21421432231 has 4 divisors (see below), whose sum is σ = 21442663600. Its totient is φ = 21400200864.

The previous prime is 21421432229. The next prime is 21421432243. The reversal of 21421432231 is 13223412412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21421432231 - 2¹ = 21421432229 is a prime.

It is a super-2 number, since 2×21421432231² (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 = 21421432196 and 21421432205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421432031) 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, 10614171 + ... + 10616188.

It is an arithmetic number, because the mean of its divisors is an integer number (5360665900).

Almost surely, 2^21421432231 is an apocalyptic number.

21421432231 is a deficient number, since it is larger than the sum of its proper divisors (21231369).

21421432231 is a wasteful number, since it uses less digits than its factorization.

21421432231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21231368.

The product of its digits is 2304, while the sum is 25.

Adding to 21421432231 its reverse (13223412412), we get a palindrome (34644844643).

The spelling of 21421432231 in words is "twenty-one billion, four hundred twenty-one million, four hundred thirty-two thousand, two hundred thirty-one".