20508987089 has 2 divisors, whose sum is σ = 20508987090. Its totient is φ = 20508987088.

The previous prime is 20508987071. The next prime is 20508987133. The reversal of 20508987089 is 98078980502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19311827089 + 1197160000 = 138967^2 + 34600^2 .

It is a cyclic number.

It is not a de Polignac number, because 20508987089 - 2¹² = 20508982993 is a prime.

It is not a weakly prime, because it can be changed into another prime (20508987589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10254493544 + 10254493545.

It is an arithmetic number, because the mean of its divisors is an integer number (10254493545).

Almost surely, 2^20508987089 is an apocalyptic number.

It is an amenable number.

20508987089 is a deficient number, since it is larger than the sum of its proper divisors (1).

20508987089 is an equidigital number, since it uses as much as digits as its factorization.

20508987089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2903040, while the sum is 56.

The spelling of 20508987089 in words is "twenty billion, five hundred eight million, nine hundred eighty-seven thousand, eighty-nine".