90128738 has 30 divisors (see below), whose sum is σ = 158875521. Its totient is φ = 38344656.

The previous prime is 90128737. The next prime is 90128741. The reversal of 90128738 is 83782109.

It can be written as a sum of positive squares in 2 ways, for example, as 89434849 + 693889 = 9457^2 + 833^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=6713.

It is not an unprimeable number, because it can be changed into a prime (90128737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 657806 + ... + 657942.

Almost surely, 2^90128738 is an apocalyptic number.

90128738 is a gapful number since it is divisible by the number (98) formed by its first and last digit.

90128738 is a deficient number, since it is larger than the sum of its proper divisors (68746783).

90128738 is an frugal number, since it uses more digits than its factorization.

90128738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304 (or 146 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 90128738 is about 9493.6156442106. The cubic root of 90128738 is about 448.3540495518.

The spelling of 90128738 in words is "ninety million, one hundred twenty-eight thousand, seven hundred thirty-eight".