21231435421 has 8 divisors (see below), whose sum is σ = 24265833344. Its totient is φ = 18197371440.

The previous prime is 21231435419. The next prime is 21231435451. The reversal of 21231435421 is 12453413212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21231435421 - 2¹ = 21231435419 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21231435421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231435451) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72091 + ... + 218311.

It is an arithmetic number, because the mean of its divisors is an integer number (3033229168).

Almost surely, 2^21231435421 is an apocalyptic number.

It is an amenable number.

21231435421 is a deficient number, since it is larger than the sum of its proper divisors (3034397923).

21231435421 is a wasteful number, since it uses less digits than its factorization.

21231435421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166971.

The product of its digits is 5760, while the sum is 28.

Adding to 21231435421 its reverse (12453413212), we get a palindrome (33684848633).

The spelling of 21231435421 in words is "twenty-one billion, two hundred thirty-one million, four hundred thirty-five thousand, four hundred twenty-one".