81565071 has 8 divisors (see below), whose sum is σ = 124289664. Its totient is φ = 46608600.

The previous prime is 81565067. The next prime is 81565073. The reversal of 81565071 is 17056518.

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

It is not a de Polignac number, because 81565071 - 2² = 81565067 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81565073) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1942005 + ... + 1942046.

It is an arithmetic number, because the mean of its divisors is an integer number (15536208).

Almost surely, 2^81565071 is an apocalyptic number.

81565071 is a deficient number, since it is larger than the sum of its proper divisors (42724593).

81565071 is a wasteful number, since it uses less digits than its factorization.

81565071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3884061.

The product of its (nonzero) digits is 8400, while the sum is 33.

The square root of 81565071 is about 9031.3382729250. The cubic root of 81565071 is about 433.6786804536.

The spelling of 81565071 in words is "eighty-one million, five hundred sixty-five thousand, seventy-one".