21836681 has 8 divisors (see below), whose sum is σ = 23779200. Its totient is φ = 19973520.

The previous prime is 21836671. The next prime is 21836699. The reversal of 21836681 is 18663812.

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 21836681 - 2¹⁴ = 21820297 is a prime.

It is a super-2 number, since 2×21836681² = 953681274191522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21836611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19265 + ... + 20366.

It is an arithmetic number, because the mean of its divisors is an integer number (2972400).

Almost surely, 2^21836681 is an apocalyptic number.

It is an amenable number.

21836681 is a deficient number, since it is larger than the sum of its proper divisors (1942519).

21836681 is a wasteful number, since it uses less digits than its factorization.

21836681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39679.

The product of its digits is 13824, while the sum is 35.

The square root of 21836681 is about 4672.9734645084. The cubic root of 21836681 is about 279.5088370579.

The spelling of 21836681 in words is "twenty-one million, eight hundred thirty-six thousand, six hundred eighty-one".