21142248 has 64 divisors (see below), whose sum is σ = 55211520. Its totient is φ = 6739200.

The previous prime is 21142243. The next prime is 21142259. The reversal of 21142248 is 84224112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21142243) 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 15 ways as a sum of consecutive naturals, for example, 116718 + ... + 116898.

It is an arithmetic number, because the mean of its divisors is an integer number (862680).

Almost surely, 2^21142248 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21142248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27605760).

21142248 is an abundant number, since it is smaller than the sum of its proper divisors (34069272).

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

21142248 is a wasteful number, since it uses less digits than its factorization.

21142248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 378 (or 374 counting only the distinct ones).

The product of its digits is 1024, while the sum is 24.

The square root of 21142248 is about 4598.0700299147. The cubic root of 21142248 is about 276.5139551744.

The spelling of 21142248 in words is "twenty-one million, one hundred forty-two thousand, two hundred forty-eight".