2565918989 has 2 divisors, whose sum is σ = 2565918990. Its totient is φ = 2565918988.

The previous prime is 2565918967. The next prime is 2565919001. The reversal of 2565918989 is 9898195652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1763160100 + 802758889 = 41990^2 + 28333^2 .

It is a cyclic number.

It is not a de Polignac number, because 2565918989 - 2¹² = 2565914893 is a prime.

It is a super-2 number, since 2×2565918989² = 13167880516221564242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2565918959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1282959494 + 1282959495.

It is an arithmetic number, because the mean of its divisors is an integer number (1282959495).

Almost surely, 2^2565918989 is an apocalyptic number.

It is an amenable number.

2565918989 is a deficient number, since it is larger than the sum of its proper divisors (1).

2565918989 is an equidigital number, since it uses as much as digits as its factorization.

2565918989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13996800, while the sum is 62.

The square root of 2565918989 is about 50654.9009376191. The cubic root of 2565918989 is about 1369.0342509140.

The spelling of 2565918989 in words is "two billion, five hundred sixty-five million, nine hundred eighteen thousand, nine hundred eighty-nine".