21906948 has 144 divisors (see below), whose sum is σ = 66890880. Its totient is φ = 5440512.

The previous prime is 21906917. The next prime is 21906949. The reversal of 21906948 is 84960912.

It is not an unprimeable number, because it can be changed into a prime (21906949) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 755398 + ... + 755426.

It is an arithmetic number, because the mean of its divisors is an integer number (464520).

Almost surely, 2^21906948 is an apocalyptic number.

21906948 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 21906948, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33445440).

21906948 is an abundant number, since it is smaller than the sum of its proper divisors (44983932).

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

21906948 is a wasteful number, since it uses less digits than its factorization.

21906948 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 21906948 is about 4680.4858722146. The cubic root of 21906948 is about 279.8083211939.

The spelling of 21906948 in words is "twenty-one million, nine hundred six thousand, nine hundred forty-eight".