91581541 has 4 divisors (see below), whose sum is σ = 91600684. Its totient is φ = 91562400.

The previous prime is 91581491. The next prime is 91581569. The reversal of 91581541 is 14518519.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12744900 + 78836641 = 3570^2 + 8879^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91581541 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91581497 and 91581506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91581041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4561 + ... + 14281.

It is an arithmetic number, because the mean of its divisors is an integer number (22900171).

Almost surely, 2^91581541 is an apocalyptic number.

It is an amenable number.

91581541 is a deficient number, since it is larger than the sum of its proper divisors (19143).

91581541 is an equidigital number, since it uses as much as digits as its factorization.

91581541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19142.

The product of its digits is 7200, while the sum is 34.

The square root of 91581541 is about 9569.8245020481. The cubic root of 91581541 is about 450.7502562694.

The spelling of 91581541 in words is "ninety-one million, five hundred eighty-one thousand, five hundred forty-one".