21248643 has 8 divisors (see below), whose sum is σ = 30510928. Its totient is φ = 13076064.

The previous prime is 21248641. The next prime is 21248651. The reversal of 21248643 is 34684212.

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

It is not a de Polignac number, because 21248643 - 2¹ = 21248641 is a prime.

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 21248643.

It is not an unprimeable number, because it can be changed into a prime (21248641) 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, 272380 + ... + 272457.

It is an arithmetic number, because the mean of its divisors is an integer number (3813866).

Almost surely, 2^21248643 is an apocalyptic number.

21248643 is a deficient number, since it is larger than the sum of its proper divisors (9262285).

21248643 is a wasteful number, since it uses less digits than its factorization.

21248643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544853.

The product of its digits is 9216, while the sum is 30.

The square root of 21248643 is about 4609.6250389809. The cubic root of 21248643 is about 276.9770167779.

The spelling of 21248643 in words is "twenty-one million, two hundred forty-eight thousand, six hundred forty-three".