20680191 has 20 divisors (see below), whose sum is σ = 35306832. Its totient is φ = 11816928.

The previous prime is 20680183. The next prime is 20680199. The reversal of 20680191 is 19108602.

It is an interprime number because it is at equal distance from previous prime (20680183) and next prime (20680199).

It is not a de Polignac number, because 20680191 - 2³ = 20680183 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20680199) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 17670 + ... + 18803.

Almost surely, 2^20680191 is an apocalyptic number.

20680191 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20680191 is a deficient number, since it is larger than the sum of its proper divisors (14626641).

20680191 is an equidigital number, since it uses as much as digits as its factorization.

20680191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36492 (or 36483 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 20680191 is about 4547.5478007383. The cubic root of 20680191 is about 274.4847254781.

Adding to 20680191 its reverse (19108602), we get a palindrome (39788793).

The spelling of 20680191 in words is "twenty million, six hundred eighty thousand, one hundred ninety-one".