21906846 has 48 divisors (see below), whose sum is σ = 54132624. Its totient is φ = 6342912.

The previous prime is 21906839. The next prime is 21906847. The reversal of 21906846 is 64860912.

It is a self number, because there is not a number n which added to its sum of digits gives 21906846.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21906847) 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 23 ways as a sum of consecutive naturals, for example, 1225 + ... + 6731.

It is an arithmetic number, because the mean of its divisors is an integer number (1127763).

Almost surely, 2^21906846 is an apocalyptic number.

21906846 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21906846, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27066312).

21906846 is an abundant number, since it is smaller than the sum of its proper divisors (32225778).

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

21906846 is a wasteful number, since it uses less digits than its factorization.

21906846 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5545 (or 5542 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 21906846 is about 4680.4749758972. The cubic root of 21906846 is about 279.8078869254.

The spelling of 21906846 in words is "twenty-one million, nine hundred six thousand, eight hundred forty-six".