21279865609045 has 4 divisors (see below), whose sum is σ = 25535838730860. Its totient is φ = 17023892487232.

The previous prime is 21279865609031. The next prime is 21279865609063. The reversal of 21279865609045 is 54090656897212.

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 5839728401809 + 15440137207236 = 2416553^2 + 3929394^2 .

It is a cyclic number.

It is not a de Polignac number, because 21279865609045 - 2⁴³ = 12483772586837 is a prime.

It is a super-2 number, since 2×21279865609045² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2127986560900 + ... + 2127986560909.

It is an arithmetic number, because the mean of its divisors is an integer number (6383959682715).

Almost surely, 2^{21279865609045} is an apocalyptic number.

It is an amenable number.

21279865609045 is a deficient number, since it is larger than the sum of its proper divisors (4255973121815).

21279865609045 is an equidigital number, since it uses as much as digits as its factorization.

21279865609045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4255973121814.

The product of its (nonzero) digits is 65318400, while the sum is 64.

The spelling of 21279865609045 in words is "twenty-one trillion, two hundred seventy-nine billion, eight hundred sixty-five million, six hundred nine thousand, forty-five".