72155618 has 4 divisors (see below), whose sum is σ = 108233430. Its totient is φ = 36077808.

The previous prime is 72155543. The next prime is 72155621. The reversal of 72155618 is 81655127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81655127 = 313 ⋅260879.

It can be written as a sum of positive squares in only one way, i.e., 55696369 + 16459249 = 7463^2 + 4057^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18038903 + ... + 18038906.

Almost surely, 2^72155618 is an apocalyptic number.

72155618 is a deficient number, since it is larger than the sum of its proper divisors (36077812).

72155618 is a wasteful number, since it uses less digits than its factorization.

72155618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36077811.

The product of its digits is 16800, while the sum is 35.

The square root of 72155618 is about 8494.4463033208. The cubic root of 72155618 is about 416.3162697532.

The spelling of 72155618 in words is "seventy-two million, one hundred fifty-five thousand, six hundred eighteen".