21488144 has 10 divisors (see below), whose sum is σ = 41633310. Its totient is φ = 10744064.

The previous prime is 21488143. The next prime is 21488171. The reversal of 21488144 is 44188412.

It can be written as a sum of positive squares in only one way, i.e., 16908544 + 4579600 = 4112^2 + 2140^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21488144.

It is not an unprimeable number, because it can be changed into a prime (21488143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 671489 + ... + 671520.

It is an arithmetic number, because the mean of its divisors is an integer number (4163331).

Almost surely, 2^21488144 is an apocalyptic number.

It is an amenable number.

21488144 is a deficient number, since it is larger than the sum of its proper divisors (20145166).

21488144 is a wasteful number, since it uses less digits than its factorization.

21488144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1343017 (or 1343011 counting only the distinct ones).

The product of its digits is 8192, while the sum is 32.

The square root of 21488144 is about 4635.5306060903. The cubic root of 21488144 is about 278.0137667216.

The spelling of 21488144 in words is "twenty-one million, four hundred eighty-eight thousand, one hundred forty-four".