21128283 has 40 divisors (see below), whose sum is σ = 35963136. Its totient is φ = 12236400.

The previous prime is 21128281. The next prime is 21128293. The reversal of 21128283 is 38282112.

It is not a de Polignac number, because 21128283 - 2¹ = 21128281 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21128281) 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 39 ways as a sum of consecutive naturals, for example, 19978 + ... + 21008.

Almost surely, 2^21128283 is an apocalyptic number.

21128283 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21128283 is a deficient number, since it is larger than the sum of its proper divisors (14834853).

21128283 is a wasteful number, since it uses less digits than its factorization.

21128283 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1077 (or 1068 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 21128283 is about 4596.5512071552. The cubic root of 21128283 is about 276.4530602323.

The spelling of 21128283 in words is "twenty-one million, one hundred twenty-eight thousand, two hundred eighty-three".