20006531 has 2 divisors, whose sum is σ = 20006532. Its totient is φ = 20006530.

The previous prime is 20006509. The next prime is 20006533. The reversal of 20006531 is 13560002.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20006531 - 2¹⁰ = 20005507 is a prime.

It is a super-2 number, since 2×20006531² = 800522565307922, which contains 22 as substring.

Together with 20006533, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20006533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10003265 + 10003266.

It is an arithmetic number, because the mean of its divisors is an integer number (10003266).

Almost surely, 2^20006531 is an apocalyptic number.

20006531 is a deficient number, since it is larger than the sum of its proper divisors (1).

20006531 is an equidigital number, since it uses as much as digits as its factorization.

20006531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 20006531 is about 4472.8660833966. The cubic root of 20006531 is about 271.4713048797.

Adding to 20006531 its reverse (13560002), we get a palindrome (33566533).

The spelling of 20006531 in words is "twenty million, six thousand, five hundred thirty-one".