20531554321 has 2 divisors, whose sum is σ = 20531554322. Its totient is φ = 20531554320.

The previous prime is 20531554319. The next prime is 20531554331. The reversal of 20531554321 is 12345513502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10563728400 + 9967825921 = 102780^2 + 99839^2 .

It is a cyclic number.

It is not a de Polignac number, because 20531554321 - 2¹ = 20531554319 is a prime.

Together with 20531554319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20531554331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10265777160 + 10265777161.

It is an arithmetic number, because the mean of its divisors is an integer number (10265777161).

Almost surely, 2^20531554321 is an apocalyptic number.

It is an amenable number.

20531554321 is a deficient number, since it is larger than the sum of its proper divisors (1).

20531554321 is an equidigital number, since it uses as much as digits as its factorization.

20531554321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18000, while the sum is 31.

The spelling of 20531554321 in words is "twenty billion, five hundred thirty-one million, five hundred fifty-four thousand, three hundred twenty-one".