21559078297 has 4 divisors (see below), whose sum is σ = 22302494820. Its totient is φ = 20815661776.

The previous prime is 21559078253. The next prime is 21559078319. The reversal of 21559078297 is 79287095512.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4632027481 + 16927050816 = 68059^2 + 130104^2 .

It is a cyclic number.

It is not a de Polignac number, because 21559078297 - 2⁷ = 21559078169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21559078997) 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, 371708218 + ... + 371708275.

It is an arithmetic number, because the mean of its divisors is an integer number (5575623705).

Almost surely, 2^21559078297 is an apocalyptic number.

It is an amenable number.

21559078297 is a deficient number, since it is larger than the sum of its proper divisors (743416523).

21559078297 is an equidigital number, since it uses as much as digits as its factorization.

21559078297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 743416522.

The product of its (nonzero) digits is 3175200, while the sum is 55.

The spelling of 21559078297 in words is "twenty-one billion, five hundred fifty-nine million, seventy-eight thousand, two hundred ninety-seven".