21043533415 has 4 divisors (see below), whose sum is σ = 25252240104. Its totient is φ = 16834826728.

The previous prime is 21043533341. The next prime is 21043533431. The reversal of 21043533415 is 51433534012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21043533415 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2104353337 + ... + 2104353346.

It is an arithmetic number, because the mean of its divisors is an integer number (6313060026).

Almost surely, 2^21043533415 is an apocalyptic number.

21043533415 is a deficient number, since it is larger than the sum of its proper divisors (4208706689).

21043533415 is an equidigital number, since it uses as much as digits as its factorization.

21043533415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4208706688.

The product of its (nonzero) digits is 21600, while the sum is 31.

The spelling of 21043533415 in words is "twenty-one billion, forty-three million, five hundred thirty-three thousand, four hundred fifteen".