91638722 has 18 divisors (see below), whose sum is σ = 160065747. Its totient is φ = 39233124.

The previous prime is 91638709. The next prime is 91638727. The reversal of 91638722 is 22783619.

It can be written as a sum of positive squares in only one way, i.e., 45819361 + 45819361 = 6769^2 + 6769^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=6769.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91638727) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 94283 + ... + 95249.

Almost surely, 2^91638722 is an apocalyptic number.

91638722 is a deficient number, since it is larger than the sum of its proper divisors (68427025).

91638722 is an frugal number, since it uses more digits than its factorization.

91638722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1950 (or 976 counting only the distinct ones).

The product of its digits is 36288, while the sum is 38.

The square root of 91638722 is about 9572.8116037035. The cubic root of 91638722 is about 450.8440487801.

The spelling of 91638722 in words is "ninety-one million, six hundred thirty-eight thousand, seven hundred twenty-two".