72170661 has 16 divisors (see below), whose sum is σ = 102904128. Its totient is φ = 44832000.

The previous prime is 72170621. The next prime is 72170663. The reversal of 72170661 is 16607127.

It is a happy number.

It is not a de Polignac number, because 72170661 - 2⁶ = 72170597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72170663) 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 15 ways as a sum of consecutive naturals, for example, 1855 + ... + 12156.

It is an arithmetic number, because the mean of its divisors is an integer number (6431508).

Almost surely, 2^72170661 is an apocalyptic number.

It is an amenable number.

72170661 is a deficient number, since it is larger than the sum of its proper divisors (30733467).

72170661 is a wasteful number, since it uses less digits than its factorization.

72170661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14132.

The product of its (nonzero) digits is 3528, while the sum is 30.

The square root of 72170661 is about 8495.3317180673. The cubic root of 72170661 is about 416.3451989420.

Adding to 72170661 its reverse (16607127), we get a palindrome (88777788).

The spelling of 72170661 in words is "seventy-two million, one hundred seventy thousand, six hundred sixty-one".