21212310131 has 4 divisors (see below), whose sum is σ = 21213633264. Its totient is φ = 21210987000.

The previous prime is 21212310127. The next prime is 21212310137. The reversal of 21212310131 is 13101321212.

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 21212310131 - 2² = 21212310127 is a prime.

It is a super-2 number, since 2×21212310131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212310137) 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, 637220 + ... + 669681.

It is an arithmetic number, because the mean of its divisors is an integer number (5303408316).

Almost surely, 2^21212310131 is an apocalyptic number.

21212310131 is a deficient number, since it is larger than the sum of its proper divisors (1323133).

21212310131 is a wasteful number, since it uses less digits than its factorization.

21212310131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1323132.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21212310131 its reverse (13101321212), we get a palindrome (34313631343).

The spelling of 21212310131 in words is "twenty-one billion, two hundred twelve million, three hundred ten thousand, one hundred thirty-one".