20615506789 has 2 divisors, whose sum is σ = 20615506790. Its totient is φ = 20615506788.

The previous prime is 20615506729. The next prime is 20615506801. The reversal of 20615506789 is 98760551602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17525258689 + 3090248100 = 132383^2 + 55590^2 .

It is a cyclic number.

It is not a de Polignac number, because 20615506789 - 2²¹ = 20613409637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20615506729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10307753394 + 10307753395.

It is an arithmetic number, because the mean of its divisors is an integer number (10307753395).

Almost surely, 2^20615506789 is an apocalyptic number.

It is an amenable number.

20615506789 is a deficient number, since it is larger than the sum of its proper divisors (1).

20615506789 is an equidigital number, since it uses as much as digits as its factorization.

20615506789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 907200, while the sum is 49.

The spelling of 20615506789 in words is "twenty billion, six hundred fifteen million, five hundred six thousand, seven hundred eighty-nine".