72165406 has 4 divisors (see below), whose sum is σ = 108248112. Its totient is φ = 36082702.

The previous prime is 72165389. The next prime is 72165407. The reversal of 72165406 is 60456127.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60456127 = 7229 ⋅8363.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72165407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18041350 + ... + 18041353.

It is an arithmetic number, because the mean of its divisors is an integer number (27062028).

Almost surely, 2^72165406 is an apocalyptic number.

72165406 is a deficient number, since it is larger than the sum of its proper divisors (36082706).

72165406 is a wasteful number, since it uses less digits than its factorization.

72165406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36082705.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 72165406 is about 8495.0224249263. The cubic root of 72165406 is about 416.3350935099.

The spelling of 72165406 in words is "seventy-two million, one hundred sixty-five thousand, four hundred six".