21289024 has 14 divisors (see below), whose sum is σ = 42245534. Its totient is φ = 10644480.

The previous prime is 21289001. The next prime is 21289027. The reversal of 21289024 is 42098212.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 5607424 = 3960^2 + 2368^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21288983 and 21289001.

It is not an unprimeable number, because it can be changed into a prime (21289027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166257 + ... + 166384.

Almost surely, 2^21289024 is an apocalyptic number.

It is an amenable number.

21289024 is a deficient number, since it is larger than the sum of its proper divisors (20956510).

21289024 is an equidigital number, since it uses as much as digits as its factorization.

21289024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332653 (or 332643 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21289024 is about 4614.0030342426. The cubic root of 21289024 is about 277.1523617995.

Subtracting from 21289024 its sum of digits (28), we obtain a square (21288996 = 4614²).

The spelling of 21289024 in words is "twenty-one million, two hundred eighty-nine thousand, twenty-four".