21751304131 has 4 divisors (see below), whose sum is σ = 21871477264. Its totient is φ = 21631131000.

The previous prime is 21751304129. The next prime is 21751304149. The reversal of 21751304131 is 13140315712.

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 21751304131 - 2¹ = 21751304129 is a prime.

It is a super-2 number, since 2×21751304131² (a number of 21 digits) contains 22 as substring.

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 21751304131.

It is not an unprimeable number, because it can be changed into a prime (21751304111) 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, 60086295 + ... + 60086656.

It is an arithmetic number, because the mean of its divisors is an integer number (5467869316).

Almost surely, 2^21751304131 is an apocalyptic number.

21751304131 is a deficient number, since it is larger than the sum of its proper divisors (120173133).

21751304131 is a wasteful number, since it uses less digits than its factorization.

21751304131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120173132.

The product of its (nonzero) digits is 2520, while the sum is 28.

Adding to 21751304131 its reverse (13140315712), we get a palindrome (34891619843).

The spelling of 21751304131 in words is "twenty-one billion, seven hundred fifty-one million, three hundred four thousand, one hundred thirty-one".