72165805 has 8 divisors (see below), whose sum is σ = 87131232. Its totient is φ = 57377808.

The previous prime is 72165787. The next prime is 72165809. The reversal of 72165805 is 50856127.

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 72165805 - 2⁹ = 72165293 is a prime.

It is a super-2 number, since 2×72165805² = 10415806822596050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72165809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43459 + ... + 45088.

It is an arithmetic number, because the mean of its divisors is an integer number (10891404).

Almost surely, 2^72165805 is an apocalyptic number.

It is an amenable number.

72165805 is a deficient number, since it is larger than the sum of its proper divisors (14965427).

72165805 is a wasteful number, since it uses less digits than its factorization.

72165805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88715.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 72165805 is about 8495.0459092344. The cubic root of 72165805 is about 416.3358608092.

The spelling of 72165805 in words is "seventy-two million, one hundred sixty-five thousand, eight hundred five".