91128640 has 28 divisors (see below), whose sum is σ = 217000836. Its totient is φ = 36451328.

The previous prime is 91128637. The next prime is 91128641. The reversal of 91128640 is 4682119.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 57395776 + 33732864 = 7576^2 + 5808^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91128641) 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 3 ways as a sum of consecutive naturals, for example, 142069 + ... + 142708.

Almost surely, 2^91128640 is an apocalyptic number.

It is an amenable number.

91128640 is an abundant number, since it is smaller than the sum of its proper divisors (125872196).

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

91128640 is a wasteful number, since it uses less digits than its factorization.

91128640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284794 (or 284784 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 91128640 is about 9546.1322010540. The cubic root of 91128640 is about 450.0059916898.

The spelling of 91128640 in words is "ninety-one million, one hundred twenty-eight thousand, six hundred forty".