21256982 has 8 divisors (see below), whose sum is σ = 31907952. Its totient is φ = 10621000.

The previous prime is 21256931. The next prime is 21256997. The reversal of 21256982 is 28965212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

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 in 3 ways as a sum of consecutive naturals, for example, 1007 + ... + 6597.

It is an arithmetic number, because the mean of its divisors is an integer number (3988494).

Almost surely, 2^21256982 is an apocalyptic number.

21256982 is a deficient number, since it is larger than the sum of its proper divisors (10650970).

21256982 is a wasteful number, since it uses less digits than its factorization.

21256982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7494.

The product of its digits is 17280, while the sum is 35.

The square root of 21256982 is about 4610.5294706790. The cubic root of 21256982 is about 277.0132451190.

The spelling of 21256982 in words is "twenty-one million, two hundred fifty-six thousand, nine hundred eighty-two".