21427107524257 has 4 divisors (see below), whose sum is σ = 21685265446320. Its totient is φ = 21168949602196.

The previous prime is 21427107524239. The next prime is 21427107524299. The reversal of 21427107524257 is 75242570172412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21427107524257 - 2¹¹ = 21427107522209 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21427107524257.

It is not an unprimeable number, because it can be changed into a prime (21427107524057) 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, 129078960907 + ... + 129078961072.

It is an arithmetic number, because the mean of its divisors is an integer number (5421316361580).

Almost surely, 2^{21427107524257} is an apocalyptic number.

It is an amenable number.

21427107524257 is a deficient number, since it is larger than the sum of its proper divisors (258157922063).

21427107524257 is an equidigital number, since it uses as much as digits as its factorization.

21427107524257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258157922062.

The product of its (nonzero) digits is 2195200, while the sum is 49.

Adding to 21427107524257 its reverse (75242570172412), we get a palindrome (96669677696669).

The spelling of 21427107524257 in words is "twenty-one trillion, four hundred twenty-seven billion, one hundred seven million, five hundred twenty-four thousand, two hundred fifty-seven".