81606133 has 4 divisors (see below), whose sum is σ = 93264160. Its totient is φ = 69948108.

The previous prime is 81606101. The next prime is 81606157. The reversal of 81606133 is 33160618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81606133 - 2⁵ = 81606101 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 (81601133) 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 3 ways as a sum of consecutive naturals, for example, 5829003 + ... + 5829016.

It is an arithmetic number, because the mean of its divisors is an integer number (23316040).

Almost surely, 2^81606133 is an apocalyptic number.

It is an amenable number.

81606133 is a deficient number, since it is larger than the sum of its proper divisors (11658027).

81606133 is a wasteful number, since it uses less digits than its factorization.

81606133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11658026.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 81606133 is about 9033.6112933865. The cubic root of 81606133 is about 433.7514433258.

The spelling of 81606133 in words is "eighty-one million, six hundred six thousand, one hundred thirty-three".