21298321 has 8 divisors (see below), whose sum is σ = 23529600. Its totient is φ = 19116240.

The previous prime is 21298309. The next prime is 21298327. The reversal of 21298321 is 12389212.

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

It is not a de Polignac number, because 21298321 - 2¹¹ = 21296273 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21298321.

It is not an unprimeable number, because it can be changed into a prime (21298327) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11386 + ... + 13123.

It is an arithmetic number, because the mean of its divisors is an integer number (2941200).

Almost surely, 2^21298321 is an apocalyptic number.

It is an amenable number.

21298321 is a deficient number, since it is larger than the sum of its proper divisors (2231279).

21298321 is a wasteful number, since it uses less digits than its factorization.

21298321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24599.

The product of its digits is 1728, while the sum is 28.

The square root of 21298321 is about 4615.0104008550. The cubic root of 21298321 is about 277.1927004346.

The spelling of 21298321 in words is "twenty-one million, two hundred ninety-eight thousand, three hundred twenty-one".