21806148 has 96 divisors (see below), whose sum is σ = 65981440. Its totient is φ = 5443200.

The previous prime is 21806143. The next prime is 21806149. The reversal of 21806148 is 84160812.

21806148 is nontrivially palindromic in base 11.

It is not an unprimeable number, because it can be changed into a prime (21806143) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 20223 + ... + 21273.

Almost surely, 2^21806148 is an apocalyptic number.

21806148 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 21806148, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32990720).

21806148 is an abundant number, since it is smaller than the sum of its proper divisors (44175292).

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

21806148 is a wasteful number, since it uses less digits than its factorization.

21806148 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1097 (or 1095 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 21806148 is about 4669.7053440233. The cubic root of 21806148 is about 279.3785024760.

The spelling of 21806148 in words is "twenty-one million, eight hundred six thousand, one hundred forty-eight".