20681091 has 12 divisors (see below), whose sum is σ = 30319432. Its totient is φ = 13581216.

The previous prime is 20681083. The next prime is 20681107. The reversal of 20681091 is 19018602.

It is not a de Polignac number, because 20681091 - 2³ = 20681083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20681021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16546 + ... + 17751.

Almost surely, 2^20681091 is an apocalyptic number.

20681091 is a deficient number, since it is larger than the sum of its proper divisors (9638341).

20681091 is a wasteful number, since it uses less digits than its factorization.

20681091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34370 (or 34367 counting only the distinct ones).

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

The square root of 20681091 is about 4547.6467540916. The cubic root of 20681091 is about 274.4887072703.

Adding to 20681091 its reverse (19018602), we get a palindrome (39699693).

The spelling of 20681091 in words is "twenty million, six hundred eighty-one thousand, ninety-one".