20867681 has 16 divisors (see below), whose sum is σ = 23040000. Its totient is φ = 18824400.

The previous prime is 20867669. The next prime is 20867701. The reversal of 20867681 is 18676802.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20867681 is a prime.

It is a super-2 number, since 2×20867681² = 870920220635522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20867281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41570 + ... + 42068.

It is an arithmetic number, because the mean of its divisors is an integer number (1440000).

Almost surely, 2^20867681 is an apocalyptic number.

It is an amenable number.

20867681 is a deficient number, since it is larger than the sum of its proper divisors (2172319).

20867681 is a wasteful number, since it uses less digits than its factorization.

20867681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 620.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 20867681 is about 4568.1156946820. The cubic root of 20867681 is about 275.3117390422.

The spelling of 20867681 in words is "twenty million, eight hundred sixty-seven thousand, six hundred eighty-one".