20696891 has 4 divisors (see below), whose sum is σ = 20706000. Its totient is φ = 20687784.

The previous prime is 20696881. The next prime is 20696911. The reversal of 20696891 is 19869602.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19869602 = 2 ⋅9934801.

It is a cyclic number.

It is not a de Polignac number, because 20696891 - 2⁶ = 20696827 is a prime.

It is a super-2 number, since 2×20696891² = 856722594131762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20696881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1970 + ... + 6728.

It is an arithmetic number, because the mean of its divisors is an integer number (5176500).

Almost surely, 2^20696891 is an apocalyptic number.

20696891 is a deficient number, since it is larger than the sum of its proper divisors (9109).

20696891 is an equidigital number, since it uses as much as digits as its factorization.

20696891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9108.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 20696891 is about 4549.3835846189. The cubic root of 20696891 is about 274.5585910367.

The spelling of 20696891 in words is "twenty million, six hundred ninety-six thousand, eight hundred ninety-one".