20686785 has 32 divisors (see below), whose sum is σ = 38019072. Its totient is φ = 9408960.

The previous prime is 20686781. The next prime is 20686789. The reversal of 20686785 is 58768602.

It is an interprime number because it is at equal distance from previous prime (20686781) and next prime (20686789).

It is not a de Polignac number, because 20686785 - 2² = 20686781 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20686781) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28092 + ... + 28818.

It is an arithmetic number, because the mean of its divisors is an integer number (1188096).

Almost surely, 2^20686785 is an apocalyptic number.

It is an amenable number.

20686785 is a deficient number, since it is larger than the sum of its proper divisors (17332287).

20686785 is a wasteful number, since it uses less digits than its factorization.

20686785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1013.

The product of its (nonzero) digits is 161280, while the sum is 42.

The square root of 20686785 is about 4548.2727490774. The cubic root of 20686785 is about 274.5138960653.

The spelling of 20686785 in words is "twenty million, six hundred eighty-six thousand, seven hundred eighty-five".