81418405 has 8 divisors (see below), whose sum is σ = 98709912. Its totient is φ = 64462848.

The previous prime is 81418373. The next prime is 81418409. The reversal of 81418405 is 50481418.

It can be written as a sum of positive squares in 4 ways, for example, as 1976836 + 79441569 = 1406^2 + 8913^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81418405 - 2⁵ = 81418373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81418409) 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 7 ways as a sum of consecutive naturals, for example, 83452 + ... + 84421.

It is an arithmetic number, because the mean of its divisors is an integer number (12338739).

Almost surely, 2^81418405 is an apocalyptic number.

It is an amenable number.

81418405 is a deficient number, since it is larger than the sum of its proper divisors (17291507).

81418405 is a wasteful number, since it uses less digits than its factorization.

81418405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167975.

The product of its (nonzero) digits is 5120, while the sum is 31.

The square root of 81418405 is about 9023.2147818835. The cubic root of 81418405 is about 433.4185851335.

The spelling of 81418405 in words is "eighty-one million, four hundred eighteen thousand, four hundred five".