21171276 has 72 divisors (see below), whose sum is σ = 63292320. Its totient is φ = 5838336.

The previous prime is 21171253. The next prime is 21171313. The reversal of 21171276 is 67217112.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5860 + ... + 8756.

It is an arithmetic number, because the mean of its divisors is an integer number (879060).

Almost surely, 2^21171276 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21171276, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31646160).

21171276 is an abundant number, since it is smaller than the sum of its proper divisors (42121044).

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

21171276 is a wasteful number, since it uses less digits than its factorization.

21171276 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2943 (or 2938 counting only the distinct ones).

The product of its digits is 1176, while the sum is 27.

The square root of 21171276 is about 4601.2254889323. The cubic root of 21171276 is about 276.6404471854.

Adding to 21171276 its reverse (67217112), we get a palindrome (88388388).

The spelling of 21171276 in words is "twenty-one million, one hundred seventy-one thousand, two hundred seventy-six".