91038978 has 56 divisors (see below), whose sum is σ = 216846828. Its totient is φ = 28553472.

The previous prime is 91038973. The next prime is 91038989. The reversal of 91038978 is 87983019.

It can be written as a sum of positive squares in 2 ways, for example, as 89813529 + 1225449 = 9477^2 + 1107^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (91038973) 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 in 27 ways as a sum of consecutive naturals, for example, 22950 + ... + 26622.

Almost surely, 2^91038978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91038978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108423414).

91038978 is an abundant number, since it is smaller than the sum of its proper divisors (125807850).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91038978 is a wasteful number, since it uses less digits than its factorization.

91038978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3710 (or 3695 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 91038978 is about 9541.4347977650. The cubic root of 91038978 is about 449.8583554198.

It can be divided in two parts, 9103 and 8978, that added together give a palindrome (18081).

The spelling of 91038978 in words is "ninety-one million, thirty-eight thousand, nine hundred seventy-eight".