21242122031 has 4 divisors (see below), whose sum is σ = 22876131432. Its totient is φ = 19608112632.

The previous prime is 21242122019. The next prime is 21242122061. The reversal of 21242122031 is 13022124212.

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-21242122031 is a prime.

It is a super-2 number, since 2×21242122031² (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 = 21242121994 and 21242122012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242122001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 817004681 + ... + 817004706.

It is an arithmetic number, because the mean of its divisors is an integer number (5719032858).

Almost surely, 2^21242122031 is an apocalyptic number.

21242122031 is a deficient number, since it is larger than the sum of its proper divisors (1634009401).

21242122031 is a wasteful number, since it uses less digits than its factorization.

21242122031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1634009400.

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21242122031 its reverse (13022124212), we get a palindrome (34264246243).

The spelling of 21242122031 in words is "twenty-one billion, two hundred forty-two million, one hundred twenty-two thousand, thirty-one".