21729342259 has 4 divisors (see below), whose sum is σ = 21731859216. Its totient is φ = 21726825304.

The previous prime is 21729342233. The next prime is 21729342281. The reversal of 21729342259 is 95224392712.

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 21729342259 - 2¹⁵ = 21729309491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21729342209) by changing a digit.

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, 1245484 + ... + 1262809.

It is an arithmetic number, because the mean of its divisors is an integer number (5432964804).

Almost surely, 2^21729342259 is an apocalyptic number.

21729342259 is a deficient number, since it is larger than the sum of its proper divisors (2516957).

21729342259 is an equidigital number, since it uses as much as digits as its factorization.

21729342259 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2516956.

The product of its digits is 544320, while the sum is 46.

The spelling of 21729342259 in words is "twenty-one billion, seven hundred twenty-nine million, three hundred forty-two thousand, two hundred fifty-nine".