2091543581 has 4 divisors (see below), whose sum is σ = 2091691164. Its totient is φ = 2091396000.

The previous prime is 2091543563. The next prime is 2091543589. The reversal of 2091543581 is 1853451902.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1508079556 + 583464025 = 38834^2 + 24155^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2091543581 is a prime.

It is a super-2 number, since 2×2091543581² = 8749109102444607122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2091543589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49970 + ... + 81731.

It is an arithmetic number, because the mean of its divisors is an integer number (522922791).

Almost surely, 2^2091543581 is an apocalyptic number.

It is an amenable number.

2091543581 is a deficient number, since it is larger than the sum of its proper divisors (147583).

2091543581 is a wasteful number, since it uses less digits than its factorization.

2091543581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147582.

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 2091543581 is about 45733.3967795964. The cubic root of 2091543581 is about 1278.8579455612.

The spelling of 2091543581 in words is "two billion, ninety-one million, five hundred forty-three thousand, five hundred eighty-one".