90128642 has 4 divisors (see below), whose sum is σ = 135192966. Its totient is φ = 45064320.

The previous prime is 90128641. The next prime is 90128669. The reversal of 90128642 is 24682109.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24682109 = 4271 ⋅5779.

It can be written as a sum of positive squares in only one way, i.e., 82283041 + 7845601 = 9071^2 + 2801^2 .

It is a junction number, because it is equal to n+sod(n) for n = 90128599 and 90128608.

It is not an unprimeable number, because it can be changed into a prime (90128641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22532159 + ... + 22532162.

Almost surely, 2^90128642 is an apocalyptic number.

90128642 is a deficient number, since it is larger than the sum of its proper divisors (45064324).

90128642 is a wasteful number, since it uses less digits than its factorization.

90128642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45064323.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 90128642 is about 9493.6105881798. The cubic root of 90128642 is about 448.3538903647.

The spelling of 90128642 in words is "ninety million, one hundred twenty-eight thousand, six hundred forty-two".