21363643 has 8 divisors (see below), whose sum is σ = 24594912. Its totient is φ = 18177216.

The previous prime is 21363637. The next prime is 21363659. The reversal of 21363643 is 34636312.

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

It is a cyclic number.

It is not a de Polignac number, because 21363643 - 2¹⁷ = 21232571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21363613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10180 + ... + 12097.

It is an arithmetic number, because the mean of its divisors is an integer number (3074364).

Almost surely, 2^21363643 is an apocalyptic number.

21363643 is a deficient number, since it is larger than the sum of its proper divisors (3231269).

21363643 is a wasteful number, since it uses less digits than its factorization.

21363643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22421.

The product of its digits is 7776, while the sum is 28.

The square root of 21363643 is about 4622.0821065836. The cubic root of 21363643 is about 277.4757947667.

Adding to 21363643 its reverse (34636312), we get a palindrome (55999955).

The spelling of 21363643 in words is "twenty-one million, three hundred sixty-three thousand, six hundred forty-three".