81418387 has 4 divisors (see below), whose sum is σ = 81664696. Its totient is φ = 81172080.

The previous prime is 81418373. The next prime is 81418409. The reversal of 81418387 is 78381418.

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

It is a cyclic number.

It is not a de Polignac number, because 81418387 - 2²³ = 73029779 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81418487) 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, 122658 + ... + 123319.

It is an arithmetic number, because the mean of its divisors is an integer number (20416174).

Almost surely, 2^81418387 is an apocalyptic number.

81418387 is a deficient number, since it is larger than the sum of its proper divisors (246309).

81418387 is a wasteful number, since it uses less digits than its factorization.

81418387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246308.

The product of its digits is 43008, while the sum is 40.

The square root of 81418387 is about 9023.2137844562. The cubic root of 81418387 is about 433.4185531934.

The spelling of 81418387 in words is "eighty-one million, four hundred eighteen thousand, three hundred eighty-seven".