21450544257 has 24 divisors (see below), whose sum is σ = 31657064544. Its totient is φ = 12873967744.

The previous prime is 21450544249. The next prime is 21450544267. The reversal of 21450544257 is 75244505412.

It is not a de Polignac number, because 21450544257 - 2³ = 21450544249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21450544267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 370563 + ... + 424520.

It is an arithmetic number, because the mean of its divisors is an integer number (1319044356).

Almost surely, 2^21450544257 is an apocalyptic number.

It is an amenable number.

21450544257 is a deficient number, since it is larger than the sum of its proper divisors (10206520287).

21450544257 is a wasteful number, since it uses less digits than its factorization.

21450544257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795149 (or 795126 counting only the distinct ones).

The product of its (nonzero) digits is 224000, while the sum is 39.

The spelling of 21450544257 in words is "twenty-one billion, four hundred fifty million, five hundred forty-four thousand, two hundred fifty-seven".