21242122431 has 4 divisors (see below), whose sum is σ = 28322829912. Its totient is φ = 14161414952.

The previous prime is 21242122423. The next prime is 21242122457. The reversal of 21242122431 is 13422124212.

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 21242122431 - 2³ = 21242122423 is a prime.

It is a super-2 number, since 2×21242122431² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242122471) 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, 3540353736 + ... + 3540353741.

It is an arithmetic number, because the mean of its divisors is an integer number (7080707478).

Almost surely, 2^21242122431 is an apocalyptic number.

21242122431 is a deficient number, since it is larger than the sum of its proper divisors (7080707481).

21242122431 is an equidigital number, since it uses as much as digits as its factorization.

21242122431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7080707480.

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

Adding to 21242122431 its reverse (13422124212), we get a palindrome (34664246643).

The spelling of 21242122431 in words is "twenty-one billion, two hundred forty-two million, one hundred twenty-two thousand, four hundred thirty-one".