21531201131 has 12 divisors (see below), whose sum is σ = 25058677896. Its totient is φ = 18422416320.

The previous prime is 21531201121. The next prime is 21531201143. The reversal of 21531201131 is 13110213512.

It is not a de Polignac number, because 21531201131 - 2¹⁸ = 21530938987 is a prime.

It is a super-2 number, since 2×21531201131² (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 (21531201121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5231585 + ... + 5235698.

It is an arithmetic number, because the mean of its divisors is an integer number (2088223158).

Almost surely, 2^21531201131 is an apocalyptic number.

21531201131 is a deficient number, since it is larger than the sum of its proper divisors (3527476765).

21531201131 is a wasteful number, since it uses less digits than its factorization.

21531201131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10467322 (or 10467311 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 20.

Adding to 21531201131 its reverse (13110213512), we get a palindrome (34641414643).

The spelling of 21531201131 in words is "twenty-one billion, five hundred thirty-one million, two hundred one thousand, one hundred thirty-one".