20155020649 has 2 divisors, whose sum is σ = 20155020650. Its totient is φ = 20155020648.

The previous prime is 20155020623. The next prime is 20155020661. The reversal of 20155020649 is 94602055102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19532019049 + 623001600 = 139757^2 + 24960^2 .

It is a cyclic number.

It is not a de Polignac number, because 20155020649 - 2⁵ = 20155020617 is a prime.

It is not a weakly prime, because it can be changed into another prime (20155020349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10077510324 + 10077510325.

It is an arithmetic number, because the mean of its divisors is an integer number (10077510325).

Almost surely, 2^20155020649 is an apocalyptic number.

It is an amenable number.

20155020649 is a deficient number, since it is larger than the sum of its proper divisors (1).

20155020649 is an equidigital number, since it uses as much as digits as its factorization.

20155020649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 34.

The spelling of 20155020649 in words is "twenty billion, one hundred fifty-five million, twenty thousand, six hundred forty-nine".