20985618 has 16 divisors (see below), whose sum is σ = 43418880. Its totient is φ = 6753936.

The previous prime is 20985617. The next prime is 20985649. The reversal of 20985618 is 81658902.

It is not an unprimeable number, because it can be changed into a prime (20985617) 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, 60130 + ... + 60477.

It is an arithmetic number, because the mean of its divisors is an integer number (2713680).

Almost surely, 2^20985618 is an apocalyptic number.

20985618 is an abundant number, since it is smaller than the sum of its proper divisors (22433262).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20985618 is a wasteful number, since it uses less digits than its factorization.

20985618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120641.

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 20985618 is about 4581.0062213448. The cubic root of 20985618 is about 275.8294209571.

The spelling of 20985618 in words is "twenty million, nine hundred eighty-five thousand, six hundred eighteen".