21676756 has 6 divisors (see below), whose sum is σ = 37934330. Its totient is φ = 10838376.

The previous prime is 21676747. The next prime is 21676763. The reversal of 21676756 is 65767612.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19660356 + 2016400 = 4434^2 + 1420^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2709591 + ... + 2709598.

Almost surely, 2^21676756 is an apocalyptic number.

It is an amenable number.

21676756 is a deficient number, since it is larger than the sum of its proper divisors (16257574).

21676756 is a wasteful number, since it uses less digits than its factorization.

21676756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5419193 (or 5419191 counting only the distinct ones).

The product of its digits is 105840, while the sum is 40.

The square root of 21676756 is about 4655.8303233688. The cubic root of 21676756 is about 278.8248194796.

The spelling of 21676756 in words is "twenty-one million, six hundred seventy-six thousand, seven hundred fifty-six".