90861438509 has 2 divisors, whose sum is σ = 90861438510. Its totient is φ = 90861438508.

The previous prime is 90861438469. The next prime is 90861438539. The reversal of 90861438509 is 90583416809.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90799768900 + 61669609 = 301330^2 + 7853^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90861438509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90861438539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45430719254 + 45430719255.

It is an arithmetic number, because the mean of its divisors is an integer number (45430719255).

Almost surely, 2^90861438509 is an apocalyptic number.

It is an amenable number.

90861438509 is a deficient number, since it is larger than the sum of its proper divisors (1).

90861438509 is an equidigital number, since it uses as much as digits as its factorization.

90861438509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1866240, while the sum is 53.

The spelling of 90861438509 in words is "ninety billion, eight hundred sixty-one million, four hundred thirty-eight thousand, five hundred nine".