20688881 has 8 divisors (see below), whose sum is σ = 22278240. Its totient is φ = 19140928.

The previous prime is 20688869. The next prime is 20688907. The reversal of 20688881 is 18888602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20688881 - 2⁶ = 20688817 is a prime.

It is a super-2 number, since 2×20688881² = 856059594064322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20618881) 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 7 ways as a sum of consecutive naturals, for example, 9311 + ... + 11316.

It is an arithmetic number, because the mean of its divisors is an integer number (2784780).

Almost surely, 2^20688881 is an apocalyptic number.

It is an amenable number.

20688881 is a deficient number, since it is larger than the sum of its proper divisors (1589359).

20688881 is a wasteful number, since it uses less digits than its factorization.

20688881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20703.

The product of its (nonzero) digits is 49152, while the sum is 41.

The square root of 20688881 is about 4548.5031603814. The cubic root of 20688881 is about 274.5231670676.

The spelling of 20688881 in words is "twenty million, six hundred eighty-eight thousand, eight hundred eighty-one".