21948668 has 36 divisors (see below), whose sum is σ = 45122112. Its totient is φ = 9313920.

The previous prime is 21948637. The next prime is 21948673. The reversal of 21948668 is 86684912.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21653 + ... + 22643.

It is an arithmetic number, because the mean of its divisors is an integer number (1253392).

Almost surely, 2^21948668 is an apocalyptic number.

21948668 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21948668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22561056).

21948668 is an abundant number, since it is smaller than the sum of its proper divisors (23173444).

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

21948668 is a wasteful number, since it uses less digits than its factorization.

21948668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1122 (or 1113 counting only the distinct ones).

The product of its digits is 165888, while the sum is 44.

The square root of 21948668 is about 4684.9405545855. The cubic root of 21948668 is about 279.9858326165.

The spelling of 21948668 in words is "twenty-one million, nine hundred forty-eight thousand, six hundred sixty-eight".