90128791 has 2 divisors, whose sum is σ = 90128792. Its totient is φ = 90128790.

The previous prime is 90128771. The next prime is 90128893. The reversal of 90128791 is 19782109.

It is a weak prime.

It is an emirp because it is prime and its reverse (19782109) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90128791 - 2⁹ = 90128279 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 90128791.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90128711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45064395 + 45064396.

It is an arithmetic number, because the mean of its divisors is an integer number (45064396).

Almost surely, 2^90128791 is an apocalyptic number.

90128791 is a deficient number, since it is larger than the sum of its proper divisors (1).

90128791 is an equidigital number, since it uses as much as digits as its factorization.

90128791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 90128791 is about 9493.6184355598. The cubic root of 90128791 is about 448.3541374364.

It can be divided in two parts, 901 and 28791, that added together give a palindrome (29692).

The spelling of 90128791 in words is "ninety million, one hundred twenty-eight thousand, seven hundred ninety-one".