21283956 has 36 divisors (see below), whose sum is σ = 53945892. Its totient is φ = 7075584.

The previous prime is 21283931. The next prime is 21283967. The reversal of 21283956 is 65938212.

It can be written as a sum of positive squares in 2 ways, for example, as 15920100 + 5363856 = 3990^2 + 2316^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 21283956.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20850 + ... + 21846.

It is an arithmetic number, because the mean of its divisors is an integer number (1498497).

Almost surely, 2^21283956 is an apocalyptic number.

It is an amenable number.

21283956 is an abundant number, since it is smaller than the sum of its proper divisors (32661936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21283956 is a wasteful number, since it uses less digits than its factorization.

21283956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1600 (or 1595 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21283956 is about 4613.4538038220. The cubic root of 21283956 is about 277.1303673726.

It can be divided in two parts, 2128 and 3956, that added together give a square (6084 = 78²).

The spelling of 21283956 in words is "twenty-one million, two hundred eighty-three thousand, nine hundred fifty-six".