21582148 has 36 divisors (see below), whose sum is σ = 45462060. Its totient is φ = 8928192.

The previous prime is 21582133. The next prime is 21582149. The reversal of 21582148 is 84128512.

It can be written as a sum of positive squares in 2 ways, for example, as 4293184 + 17288964 = 2072^2 + 4158^2 .

It is a super-2 number, since 2×21582148² = 931578224587808, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21582149) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3786 + ... + 7582.

It is an arithmetic number, because the mean of its divisors is an integer number (1262835).

Almost surely, 2^21582148 is an apocalyptic number.

21582148 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 21582148, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22731030).

21582148 is an abundant number, since it is smaller than the sum of its proper divisors (23879912).

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

21582148 is a wasteful number, since it uses less digits than its factorization.

21582148 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3844 (or 3835 counting only the distinct ones).

The product of its digits is 5120, while the sum is 31.

The square root of 21582148 is about 4645.6590490478. The cubic root of 21582148 is about 278.4185851258.

It can be divided in two parts, 21 and 582148, that added together give a square (582169 = 763²).

The spelling of 21582148 in words is "twenty-one million, five hundred eighty-two thousand, one hundred forty-eight".