91011601 has 4 divisors (see below), whose sum is σ = 93471412. Its totient is φ = 88551792.

The previous prime is 91011593. The next prime is 91011611. The reversal of 91011601 is 10611019.

It is a Cunningham number, because it is equal to 9540²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10611019 = 2081 ⋅5099.

It can be written as a sum of positive squares in 2 ways, for example, as 81432576 + 9579025 = 9024^2 + 3095^2 .

It is a cyclic number.

It is not a de Polignac number, because 91011601 - 2³ = 91011593 is a prime.

It is a super-2 number, since 2×91011601² = 16566223033166402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91011611) 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 3 ways as a sum of consecutive naturals, for example, 1229850 + ... + 1229923.

It is an arithmetic number, because the mean of its divisors is an integer number (23367853).

Almost surely, 2^91011601 is an apocalyptic number.

It is an amenable number.

91011601 is a deficient number, since it is larger than the sum of its proper divisors (2459811).

91011601 is a wasteful number, since it uses less digits than its factorization.

91011601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2459810.

The product of its (nonzero) digits is 54, while the sum is 19.

The square root of 91011601 is about 9540.0000524109. Note that the first 4 decimals coincide. The cubic root of 91011601 is about 449.8132574951.

The spelling of 91011601 in words is "ninety-one million, eleven thousand, six hundred one".