21081282 has 24 divisors (see below), whose sum is σ = 42979536. Its totient is φ = 6891984.

The previous prime is 21081259. The next prime is 21081287. The reversal of 21081282 is 28218012.

It is not an unprimeable number, because it can be changed into a prime (21081287) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 91944 + ... + 92172.

It is an arithmetic number, because the mean of its divisors is an integer number (1790814).

Almost surely, 2^21081282 is an apocalyptic number.

21081282 is an abundant number, since it is smaller than the sum of its proper divisors (21898254).

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

21081282 is an equidigital number, since it uses as much as digits as its factorization.

21081282 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530 (or 301 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 21081282 is about 4591.4357231698. The cubic root of 21081282 is about 276.2479131446.

Adding to 21081282 its reverse (28218012), we get a palindrome (49299294).

The spelling of 21081282 in words is "twenty-one million, eighty-one thousand, two hundred eighty-two".