20156516449 has 2 divisors, whose sum is σ = 20156516450. Its totient is φ = 20156516448.

The previous prime is 20156516357. The next prime is 20156516459. The reversal of 20156516449 is 94461565102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10786276449 + 9370240000 = 103857^2 + 96800^2 .

It is a cyclic number.

It is not a de Polignac number, because 20156516449 - 2⁷ = 20156516321 is a prime.

It is not a weakly prime, because it can be changed into another prime (20156516459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10078258224 + 10078258225.

It is an arithmetic number, because the mean of its divisors is an integer number (10078258225).

Almost surely, 2^20156516449 is an apocalyptic number.

It is an amenable number.

20156516449 is a deficient number, since it is larger than the sum of its proper divisors (1).

20156516449 is an equidigital number, since it uses as much as digits as its factorization.

20156516449 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 259200, while the sum is 43.

The spelling of 20156516449 in words is "twenty billion, one hundred fifty-six million, five hundred sixteen thousand, four hundred forty-nine".