21843402505 has 8 divisors (see below), whose sum is σ = 26278110792. Its totient is φ = 17430703488.

The previous prime is 21843402491. The next prime is 21843402509. The reversal of 21843402505 is 50520434812.

It can be written as a sum of positive squares in 4 ways, for example, as 5415340921 + 16428061584 = 73589^2 + 128172^2 .

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 21843402505 - 2¹⁹ = 21842878217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21843402509) 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, 5500132 + ... + 5504101.

It is an arithmetic number, because the mean of its divisors is an integer number (3284763849).

Almost surely, 2^21843402505 is an apocalyptic number.

It is an amenable number.

21843402505 is a deficient number, since it is larger than the sum of its proper divisors (4434708287).

21843402505 is a wasteful number, since it uses less digits than its factorization.

21843402505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11004635.

The product of its (nonzero) digits is 38400, while the sum is 34.

The spelling of 21843402505 in words is "twenty-one billion, eight hundred forty-three million, four hundred two thousand, five hundred five".