21396144 has 120 divisors (see below), whose sum is σ = 70227648. Its totient is φ = 5550720.

The previous prime is 21396119. The next prime is 21396161. The reversal of 21396144 is 44169312.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25459 + ... + 26285.

Almost surely, 2^21396144 is an apocalyptic number.

21396144 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 21396144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35113824).

21396144 is an abundant number, since it is smaller than the sum of its proper divisors (48831504).

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

21396144 is a wasteful number, since it uses less digits than its factorization.

21396144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 863 (or 850 counting only the distinct ones).

The product of its digits is 5184, while the sum is 30.

The square root of 21396144 is about 4625.5966101682. The cubic root of 21396144 is about 277.6164335683.

The spelling of 21396144 in words is "twenty-one million, three hundred ninety-six thousand, one hundred forty-four".