18711481 has 4 divisors (see below), whose sum is σ = 18789364. Its totient is φ = 18633600.

The previous prime is 18711479. The next prime is 18711487. The reversal of 18711481 is 18411781.

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 6843456 + 11868025 = 2616^2 + 3445^2 .

It is a cyclic number.

It is not a de Polignac number, because 18711481 - 2¹ = 18711479 is a prime.

It is a super-2 number, since 2×18711481² = 700239042426722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18711487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38580 + ... + 39061.

It is an arithmetic number, because the mean of its divisors is an integer number (4697341).

Almost surely, 2^18711481 is an apocalyptic number.

It is an amenable number.

18711481 is a deficient number, since it is larger than the sum of its proper divisors (77883).

18711481 is an equidigital number, since it uses as much as digits as its factorization.

18711481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77882.

The product of its digits is 1792, while the sum is 31.

The square root of 18711481 is about 4325.6769412428. The cubic root of 18711481 is about 265.4825951519.

The spelling of 18711481 in words is "eighteen million, seven hundred eleven thousand, four hundred eighty-one".