20431011531 has 96 divisors (see below), whose sum is σ = 33827466240. Its totient is φ = 10917871104.

The previous prime is 20431011511. The next prime is 20431011541. The reversal of 20431011531 is 13511013402.

It is not a de Polignac number, because 20431011531 - 2¹⁰ = 20431010507 is a prime.

It is a super-2 number, since 2×20431011531² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 20431011498 and 20431011507.

It is not an unprimeable number, because it can be changed into a prime (20431011511) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 21438151 + ... + 21439103.

It is an arithmetic number, because the mean of its divisors is an integer number (352369440).

Almost surely, 2^20431011531 is an apocalyptic number.

20431011531 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20431011531 is a deficient number, since it is larger than the sum of its proper divisors (13396454709).

20431011531 is a wasteful number, since it uses less digits than its factorization.

20431011531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1153 (or 1146 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

Adding to 20431011531 its reverse (13511013402), we get a palindrome (33942024933).

The spelling of 20431011531 in words is "twenty billion, four hundred thirty-one million, eleven thousand, five hundred thirty-one".