21405365459 has 4 divisors (see below), whose sum is σ = 21448961400. Its totient is φ = 21361769520.

The previous prime is 21405365453. The next prime is 21405365483. The reversal of 21405365459 is 95456350412.

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

It is a cyclic number.

It is not a de Polignac number, because 21405365459 - 2¹² = 21405361363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21405365453) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21797234 + ... + 21798215.

It is an arithmetic number, because the mean of its divisors is an integer number (5362240350).

Almost surely, 2^21405365459 is an apocalyptic number.

21405365459 is a deficient number, since it is larger than the sum of its proper divisors (43595941).

21405365459 is an equidigital number, since it uses as much as digits as its factorization.

21405365459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43595940.

The product of its (nonzero) digits is 648000, while the sum is 44.

The spelling of 21405365459 in words is "twenty-one billion, four hundred five million, three hundred sixty-five thousand, four hundred fifty-nine".