91638625 has 16 divisors (see below), whose sum is σ = 123164496. Its totient is φ = 67670400.

The previous prime is 91638611. The next prime is 91638629. The reversal of 91638625 is 52683619.

It can be written as a sum of positive squares in 8 ways, for example, as 54037201 + 37601424 = 7351^2 + 6132^2 .

It is not a de Polignac number, because 91638625 - 2⁷ = 91638497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91638629) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26572 + ... + 29821.

It is an arithmetic number, because the mean of its divisors is an integer number (7697781).

Almost surely, 2^91638625 is an apocalyptic number.

It is an amenable number.

91638625 is a deficient number, since it is larger than the sum of its proper divisors (31525871).

91638625 is a wasteful number, since it uses less digits than its factorization.

91638625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56421 (or 56411 counting only the distinct ones).

The product of its digits is 77760, while the sum is 40.

The square root of 91638625 is about 9572.8065372700. The cubic root of 91638625 is about 450.8438897066.

The spelling of 91638625 in words is "ninety-one million, six hundred thirty-eight thousand, six hundred twenty-five".