16591081 has 4 divisors (see below), whose sum is σ = 17867332. Its totient is φ = 15314832.

The previous prime is 16591063. The next prime is 16591093. The reversal of 16591081 is 18019561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18019561 = 7 ⋅2574223.

It can be written as a sum of positive squares in 2 ways, for example, as 3515625 + 13075456 = 1875^2 + 3616^2 .

It is not a de Polignac number, because 16591081 - 2⁵ = 16591049 is a prime.

It is a super-2 number, since 2×16591081² = 550527937497122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16591061) 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, 638106 + ... + 638131.

It is an arithmetic number, because the mean of its divisors is an integer number (4466833).

Almost surely, 2^16591081 is an apocalyptic number.

It is an amenable number.

16591081 is a deficient number, since it is larger than the sum of its proper divisors (1276251).

16591081 is a wasteful number, since it uses less digits than its factorization.

16591081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276250.

The product of its (nonzero) digits is 2160, while the sum is 31.

The square root of 16591081 is about 4073.2150692052. The cubic root of 16591081 is about 255.0497455173.

The spelling of 16591081 in words is "sixteen million, five hundred ninety-one thousand, eighty-one".