16181618 has 16 divisors (see below), whose sum is σ = 24815160. Its totient is φ = 7911936.

The previous prime is 16181611. The next prime is 16181621. The reversal of 16181618 is 81618161.

It can be written as a sum of positive squares in 4 ways, for example, as 16024009 + 157609 = 4003^2 + 397^2 .

It is a super-2 number, since 2×16181618² = 523689522195848, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (16181611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19598 + ... + 20406.

Almost surely, 2^16181618 is an apocalyptic number.

16181618 is a deficient number, since it is larger than the sum of its proper divisors (8633542).

16181618 is a wasteful number, since it uses less digits than its factorization.

16181618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1021.

The product of its digits is 2304, while the sum is 32.

The square root of 16181618 is about 4022.6381890496. The cubic root of 16181618 is about 252.9340597940.

Adding to 16181618 its reverse (81618161), we get a palindrome (97799779).

The spelling of 16181618 in words is "sixteen million, one hundred eighty-one thousand, six hundred eighteen".