20887618 has 16 divisors (see below), whose sum is σ = 32119416. Its totient is φ = 10183680.

The previous prime is 20887613. The next prime is 20887621. The reversal of 20887618 is 81678802.

It can be written as a sum of positive squares in 4 ways, for example, as 18122049 + 2765569 = 4257^2 + 1663^2 .

It is not an unprimeable number, because it can be changed into a prime (20887613) 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, 19948 + ... + 20968.

Almost surely, 2^20887618 is an apocalyptic number.

20887618 is a deficient number, since it is larger than the sum of its proper divisors (11231798).

20887618 is a wasteful number, since it uses less digits than its factorization.

20887618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1269.

The product of its (nonzero) digits is 43008, while the sum is 40.

The square root of 20887618 is about 4570.2973645049. The cubic root of 20887618 is about 275.3993888236.

The spelling of 20887618 in words is "twenty million, eight hundred eighty-seven thousand, six hundred eighteen".