18781481 has 8 divisors (see below), whose sum is σ = 20933280. Its totient is φ = 16746048.

The previous prime is 18781471. The next prime is 18781487. The reversal of 18781481 is 18418781.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18781481 is a prime.

It is a super-2 number, since 2×18781481² = 705488057106722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18781487) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28751 + ... + 29396.

It is an arithmetic number, because the mean of its divisors is an integer number (2616660).

Almost surely, 2^18781481 is an apocalyptic number.

It is an amenable number.

18781481 is a deficient number, since it is larger than the sum of its proper divisors (2151799).

18781481 is a wasteful number, since it uses less digits than its factorization.

18781481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58183.

The product of its digits is 14336, while the sum is 38.

The square root of 18781481 is about 4333.7606071402. The cubic root of 18781481 is about 265.8132416253.

The spelling of 18781481 in words is "eighteen million, seven hundred eighty-one thousand, four hundred eighty-one".