81415663 has 8 divisors (see below), whose sum is σ = 94572320. Its totient is φ = 68640480.

The previous prime is 81415661. The next prime is 81415679. The reversal of 81415663 is 36651418.

It is a happy number.

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 81415663 - 2¹ = 81415661 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 (81415661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 94908 + ... + 95761.

It is an arithmetic number, because the mean of its divisors is an integer number (11821540).

Almost surely, 2^81415663 is an apocalyptic number.

81415663 is a deficient number, since it is larger than the sum of its proper divisors (13156657).

81415663 is a wasteful number, since it uses less digits than its factorization.

81415663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190737.

The product of its digits is 17280, while the sum is 34.

The square root of 81415663 is about 9023.0628391916. The cubic root of 81415663 is about 433.4137195379.

The spelling of 81415663 in words is "eighty-one million, four hundred fifteen thousand, six hundred sixty-three".