21955686 has 16 divisors (see below), whose sum is σ = 44338944. Its totient is φ = 7247304.

The previous prime is 21955673. The next prime is 21955691. The reversal of 21955686 is 68655912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17146 + ... + 18381.

It is an arithmetic number, because the mean of its divisors is an integer number (2771184).

Almost surely, 2^21955686 is an apocalyptic number.

21955686 is an abundant number, since it is smaller than the sum of its proper divisors (22383258).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21955686 is a wasteful number, since it uses less digits than its factorization.

21955686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35635.

The product of its digits is 129600, while the sum is 42.

The square root of 21955686 is about 4685.6894903525. The cubic root of 21955686 is about 280.0156708916.

The spelling of 21955686 in words is "twenty-one million, nine hundred fifty-five thousand, six hundred eighty-six".