541081991 has 4 divisors (see below), whose sum is σ = 541181400. Its totient is φ = 540982584.

The previous prime is 541081963. The next prime is 541082021. The reversal of 541081991 is 199180145.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199180145 = 5 ⋅39836029.

It is a cyclic number.

It is not a de Polignac number, because 541081991 - 2²⁶ = 473973127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (541081901) 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, 41036 + ... + 52593.

It is an arithmetic number, because the mean of its divisors is an integer number (135295350).

Almost surely, 2^541081991 is an apocalyptic number.

541081991 is a deficient number, since it is larger than the sum of its proper divisors (99409).

541081991 is an equidigital number, since it uses as much as digits as its factorization.

541081991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99408.

The product of its (nonzero) digits is 12960, while the sum is 38.

The square root of 541081991 is about 23261.1691666606. The cubic root of 541081991 is about 814.8688064634.

The spelling of 541081991 in words is "five hundred forty-one million, eighty-one thousand, nine hundred ninety-one".