21651276 has 12 divisors (see below), whose sum is σ = 50519672. Its totient is φ = 7217088.

The previous prime is 21651271. The next prime is 21651277. The reversal of 21651276 is 67215612.

It is a tau number, because it is divible by the number of its divisors (12).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21651271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 902125 + ... + 902148.

Almost surely, 2^21651276 is an apocalyptic number.

It is an amenable number.

21651276 is an abundant number, since it is smaller than the sum of its proper divisors (28868396).

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

21651276 is a wasteful number, since it uses less digits than its factorization.

21651276 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1804280 (or 1804278 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 21651276 is about 4653.0931647669. The cubic root of 21651276 is about 278.7155281898.

Adding to 21651276 its reverse (67215612), we get a palindrome (88866888).

The spelling of 21651276 in words is "twenty-one million, six hundred fifty-one thousand, two hundred seventy-six".