20681785 has 16 divisors (see below), whose sum is σ = 27028800. Its totient is φ = 15132096.

The previous prime is 20681777. The next prime is 20681813. The reversal of 20681785 is 58718602.

It is a cyclic number.

It is not a de Polignac number, because 20681785 - 2³ = 20681777 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 999 + ... + 6508.

It is an arithmetic number, because the mean of its divisors is an integer number (1689300).

Almost surely, 2^20681785 is an apocalyptic number.

It is an amenable number.

20681785 is a deficient number, since it is larger than the sum of its proper divisors (6347015).

20681785 is a wasteful number, since it uses less digits than its factorization.

20681785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7560.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 20681785 is about 4547.7230566515. The cubic root of 20681785 is about 274.4917775956.

The spelling of 20681785 in words is "twenty million, six hundred eighty-one thousand, seven hundred eighty-five".