21421242320431 has 4 divisors (see below), whose sum is σ = 21421363554864. Its totient is φ = 21421121086000.

The previous prime is 21421242320417. The next prime is 21421242320437. The reversal of 21421242320431 is 13402324212412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21421242320431 is a prime.

It is a super-2 number, since 2×21421242320431² (a number of 27 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 = 21421242320393 and 21421242320402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421242320437) 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, 60351790 + ... + 60705691.

It is an arithmetic number, because the mean of its divisors is an integer number (5355340888716).

Almost surely, 2^{21421242320431} is an apocalyptic number.

21421242320431 is a deficient number, since it is larger than the sum of its proper divisors (121234433).

21421242320431 is a wasteful number, since it uses less digits than its factorization.

21421242320431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121234432.

The product of its (nonzero) digits is 18432, while the sum is 31.

Adding to 21421242320431 its reverse (13402324212412), we get a palindrome (34823566532843).

The spelling of 21421242320431 in words is "twenty-one trillion, four hundred twenty-one billion, two hundred forty-two million, three hundred twenty thousand, four hundred thirty-one".