72188161 has 2 divisors, whose sum is σ = 72188162. Its totient is φ = 72188160.

The previous prime is 72188153. The next prime is 72188189. The reversal of 72188161 is 16188127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51394561 + 20793600 = 7169^2 + 4560^2 .

It is a cyclic number.

It is not a de Polignac number, because 72188161 - 2³ = 72188153 is a prime.

It is a super-2 number, since 2×72188161² = 10422261177123842, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (72188101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36094080 + 36094081.

It is an arithmetic number, because the mean of its divisors is an integer number (36094081).

Almost surely, 2^72188161 is an apocalyptic number.

It is an amenable number.

72188161 is a deficient number, since it is larger than the sum of its proper divisors (1).

72188161 is an equidigital number, since it uses as much as digits as its factorization.

72188161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 34.

The square root of 72188161 is about 8496.3616330757. The cubic root of 72188161 is about 416.3788481287.

Subtracting from 72188161 its sum of digits (34), we obtain a palindrome (72188127).

The spelling of 72188161 in words is "seventy-two million, one hundred eighty-eight thousand, one hundred sixty-one".