81455999 has 8 divisors (see below), whose sum is σ = 82170288. Its totient is φ = 80745280.

The previous prime is 81455989. The next prime is 81456007. The reversal of 81455999 is 99955418.

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 81455999 - 2⁸ = 81455743 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 (81455929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63149 + ... + 64425.

It is an arithmetic number, because the mean of its divisors is an integer number (10271286).

Almost surely, 2^81455999 is an apocalyptic number.

81455999 is a deficient number, since it is larger than the sum of its proper divisors (714289).

81455999 is a wasteful number, since it uses less digits than its factorization.

81455999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1785.

The product of its digits is 583200, while the sum is 50.

The square root of 81455999 is about 9025.2977236211. The cubic root of 81455999 is about 433.4852835297.

The spelling of 81455999 in words is "eighty-one million, four hundred fifty-five thousand, nine hundred ninety-nine".