72171666 has 24 divisors (see below), whose sum is σ = 178711104. Its totient is φ = 20620440.

The previous prime is 72171653. The next prime is 72171667. The reversal of 72171666 is 66617127.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 72171666.

It is not an unprimeable number, because it can be changed into a prime (72171667) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 286270 + ... + 286521.

It is an arithmetic number, because the mean of its divisors is an integer number (7446296).

Almost surely, 2^72171666 is an apocalyptic number.

72171666 is an abundant number, since it is smaller than the sum of its proper divisors (106539438).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

72171666 is a wasteful number, since it uses less digits than its factorization.

72171666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 572806 (or 572803 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 72171666 is about 8495.3908679942. The cubic root of 72171666 is about 416.3471315139.

The spelling of 72171666 in words is "seventy-two million, one hundred seventy-one thousand, six hundred sixty-six".