21628282 has 24 divisors (see below), whose sum is σ = 35739900. Its totient is φ = 9809280.

The previous prime is 21628237. The next prime is 21628283. The reversal of 21628282 is 28282612.

It can be written as a sum of positive squares in 6 ways, for example, as 2277081 + 19351201 = 1509^2 + 4399^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21628283) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 20094 + ... + 21142.

Almost surely, 2^21628282 is an apocalyptic number.

21628282 is a deficient number, since it is larger than the sum of its proper divisors (14111618).

21628282 is a wasteful number, since it uses less digits than its factorization.

21628282 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1138 (or 1125 counting only the distinct ones).

The product of its digits is 6144, while the sum is 31.

The square root of 21628282 is about 4650.6216788726. The cubic root of 21628282 is about 278.6168264637.

The spelling of 21628282 in words is "twenty-one million, six hundred twenty-eight thousand, two hundred eighty-two".