21354144 has 96 divisors (see below), whose sum is σ = 65640960. Its totient is φ = 5951232.

The previous prime is 21354139. The next prime is 21354167. The reversal of 21354144 is 44145312.

It is a tau number, because it is divible by the number of its divisors (96).

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

It is an unprimeable number.

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, 28527 + ... + 29265.

It is an arithmetic number, because the mean of its divisors is an integer number (683760).

Almost surely, 2^21354144 is an apocalyptic number.

21354144 is a gapful number since it is divisible by the number (24) 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 21354144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32820480).

21354144 is an abundant number, since it is smaller than the sum of its proper divisors (44286816).

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

21354144 is a wasteful number, since it uses less digits than its factorization.

21354144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 802 (or 794 counting only the distinct ones).

The product of its digits is 1920, while the sum is 24.

The square root of 21354144 is about 4621.0544251285. The cubic root of 21354144 is about 277.4346636213.

Adding to 21354144 its reverse (44145312), we get a palindrome (65499456).

The spelling of 21354144 in words is "twenty-one million, three hundred fifty-four thousand, one hundred forty-four".