81606055 has 4 divisors (see below), whose sum is σ = 97927272. Its totient is φ = 65284840.

The previous prime is 81606037. The next prime is 81606071. The reversal of 81606055 is 55060618.

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

It is not a de Polignac number, because 81606055 - 2⁵ = 81606023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8160601 + ... + 8160610.

It is an arithmetic number, because the mean of its divisors is an integer number (24481818).

Almost surely, 2^81606055 is an apocalyptic number.

81606055 is a deficient number, since it is larger than the sum of its proper divisors (16321217).

81606055 is a wasteful number, since it uses less digits than its factorization.

81606055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16321216.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 81606055 is about 9033.6069761751. The cubic root of 81606055 is about 433.7513051311.

The spelling of 81606055 in words is "eighty-one million, six hundred six thousand, fifty-five".