21297982 has 4 divisors (see below), whose sum is σ = 31946976. Its totient is φ = 10648990.

The previous prime is 21297979. The next prime is 21298001. The reversal of 21297982 is 28979212.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5324494 + ... + 5324497.

It is an arithmetic number, because the mean of its divisors is an integer number (7986744).

Almost surely, 2^21297982 is an apocalyptic number.

21297982 is a deficient number, since it is larger than the sum of its proper divisors (10648994).

21297982 is a wasteful number, since it uses less digits than its factorization.

21297982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10648993.

The product of its digits is 36288, while the sum is 40.

The square root of 21297982 is about 4614.9736727310. The cubic root of 21297982 is about 277.1912297581.

The spelling of 21297982 in words is "twenty-one million, two hundred ninety-seven thousand, nine hundred eighty-two".