581481891 has 12 divisors (see below), whose sum is σ = 844775568. Its totient is φ = 385412784.

The previous prime is 581481881. The next prime is 581481907. The reversal of 581481891 is 198184185.

581481891 is a `hidden beast` number, since 5 + 81 + 481 + 8 + 91 = 666.

It is not a de Polignac number, because 581481891 - 2⁶ = 581481827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (581481851) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 185175 + ... + 188288.

It is an arithmetic number, because the mean of its divisors is an integer number (70397964).

Almost surely, 2^581481891 is an apocalyptic number.

581481891 is a deficient number, since it is larger than the sum of its proper divisors (263293677).

581481891 is a wasteful number, since it uses less digits than its factorization.

581481891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373642 (or 373639 counting only the distinct ones).

The product of its digits is 92160, while the sum is 45.

The square root of 581481891 is about 24113.9356182271. The cubic root of 581481891 is about 834.6647349464.

The spelling of 581481891 in words is "five hundred eighty-one million, four hundred eighty-one thousand, eight hundred ninety-one".