20618985 has 16 divisors (see below), whose sum is σ = 33295680. Its totient is φ = 10895040.

The previous prime is 20618981. The next prime is 20619013. The reversal of 20618985 is 58981602.

It is not a de Polignac number, because 20618985 - 2² = 20618981 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20618981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4671 + ... + 7940.

It is an arithmetic number, because the mean of its divisors is an integer number (2080980).

Almost surely, 2^20618985 is an apocalyptic number.

It is an amenable number.

20618985 is a deficient number, since it is larger than the sum of its proper divisors (12676695).

20618985 is a wasteful number, since it uses less digits than its factorization.

20618985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12728.

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

The square root of 20618985 is about 4540.8132531519. The cubic root of 20618985 is about 274.2136655456.

It can be divided in two parts, 206 and 18985, that added together give a palindrome (19191).

The spelling of 20618985 in words is "twenty million, six hundred eighteen thousand, nine hundred eighty-five".