20531321329 has 2 divisors, whose sum is σ = 20531321330. Its totient is φ = 20531321328.

The previous prime is 20531321303. The next prime is 20531321333. The reversal of 20531321329 is 92312313502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14932840000 + 5598481329 = 122200^2 + 74823^2 .

It is a cyclic number.

It is not a de Polignac number, because 20531321329 - 2¹³ = 20531313137 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20531321329.

It is not a weakly prime, because it can be changed into another prime (20531321389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10265660664 + 10265660665.

It is an arithmetic number, because the mean of its divisors is an integer number (10265660665).

Almost surely, 2^20531321329 is an apocalyptic number.

It is an amenable number.

20531321329 is a deficient number, since it is larger than the sum of its proper divisors (1).

20531321329 is an equidigital number, since it uses as much as digits as its factorization.

20531321329 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9720, while the sum is 31.

The spelling of 20531321329 in words is "twenty billion, five hundred thirty-one million, three hundred twenty-one thousand, three hundred twenty-nine".