20531605249 has 2 divisors, whose sum is σ = 20531605250. Its totient is φ = 20531605248.

The previous prime is 20531605229. The next prime is 20531605253. The reversal of 20531605249 is 94250613502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11010724624 + 9520880625 = 104932^2 + 97575^2 .

It is a cyclic number.

It is not a de Polignac number, because 20531605249 - 2⁷ = 20531605121 is a prime.

It is not a weakly prime, because it can be changed into another prime (20531605229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10265802624 + 10265802625.

It is an arithmetic number, because the mean of its divisors is an integer number (10265802625).

Almost surely, 2^20531605249 is an apocalyptic number.

It is an amenable number.

20531605249 is a deficient number, since it is larger than the sum of its proper divisors (1).

20531605249 is an equidigital number, since it uses as much as digits as its factorization.

20531605249 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64800, while the sum is 37.

The spelling of 20531605249 in words is "twenty billion, five hundred thirty-one million, six hundred five thousand, two hundred forty-nine".