21450227257 has 4 divisors (see below), whose sum is σ = 21854948580. Its totient is φ = 21045505936.

The previous prime is 21450227237. The next prime is 21450227297. The reversal of 21450227257 is 75272205412.

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 18334243216 + 3115984041 = 135404^2 + 55821^2 .

It is a cyclic number.

It is not a de Polignac number, because 21450227257 - 2⁷ = 21450227129 is a prime.

It is a super-2 number, since 2×21450227257² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21450227237) 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, 202360582 + ... + 202360687.

It is an arithmetic number, because the mean of its divisors is an integer number (5463737145).

Almost surely, 2^21450227257 is an apocalyptic number.

It is an amenable number.

21450227257 is a deficient number, since it is larger than the sum of its proper divisors (404721323).

21450227257 is an equidigital number, since it uses as much as digits as its factorization.

21450227257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404721322.

The product of its (nonzero) digits is 78400, while the sum is 37.

The spelling of 21450227257 in words is "twenty-one billion, four hundred fifty million, two hundred twenty-seven thousand, two hundred fifty-seven".