21007282 has 8 divisors (see below), whose sum is σ = 31531500. Its totient is φ = 10496784.

The previous prime is 21007253. The next prime is 21007289. The reversal of 21007282 is 28270012.

It can be written as a sum of positive squares in 2 ways, for example, as 19105641 + 1901641 = 4371^2 + 1379^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21007289) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2344 + ... + 6892.

Almost surely, 2^21007282 is an apocalyptic number.

21007282 is a deficient number, since it is larger than the sum of its proper divisors (10524218).

21007282 is a wasteful number, since it uses less digits than its factorization.

21007282 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6860.

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 21007282 is about 4583.3701574278. The cubic root of 21007282 is about 275.9243036129.

Adding to 21007282 its reverse (28270012), we get a palindrome (49277294).

The spelling of 21007282 in words is "twenty-one million, seven thousand, two hundred eighty-two".