21043455 has 16 divisors (see below), whose sum is σ = 34491744. Its totient is φ = 10949120.

The previous prime is 21043453. The next prime is 21043457. The reversal of 21043455 is 55434012.

It is an interprime number because it is at equal distance from previous prime (21043453) and next prime (21043457).

It is not a de Polignac number, because 21043455 - 2¹ = 21043453 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16494 + ... + 17723.

It is an arithmetic number, because the mean of its divisors is an integer number (2155734).

Almost surely, 2^21043455 is an apocalyptic number.

21043455 is a deficient number, since it is larger than the sum of its proper divisors (13448289).

21043455 is a wasteful number, since it uses less digits than its factorization.

21043455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34266.

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 21043455 is about 4587.3145739092. The cubic root of 21043455 is about 276.0825866066.

Adding to 21043455 its reverse (55434012), we get a palindrome (76477467).

The spelling of 21043455 in words is "twenty-one million, forty-three thousand, four hundred fifty-five".