21135283 has 4 divisors (see below), whose sum is σ = 22761088. Its totient is φ = 19509480.

The previous prime is 21135259. The next prime is 21135293. The reversal of 21135283 is 38253112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21135283 - 2¹³ = 21127091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21135223) 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, 812883 + ... + 812908.

It is an arithmetic number, because the mean of its divisors is an integer number (5690272).

Almost surely, 2^21135283 is an apocalyptic number.

21135283 is a deficient number, since it is larger than the sum of its proper divisors (1625805).

21135283 is a wasteful number, since it uses less digits than its factorization.

21135283 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1625804.

The product of its digits is 1440, while the sum is 25.

The square root of 21135283 is about 4597.3125845433. The cubic root of 21135283 is about 276.4835873658.

Adding to 21135283 its reverse (38253112), we get a palindrome (59388395).

It can be divided in two parts, 2113 and 5283, that added together give a square (7396 = 86²).

The spelling of 21135283 in words is "twenty-one million, one hundred thirty-five thousand, two hundred eighty-three".