25564492321 has 9 divisors (see below), whose sum is σ = 25700961433.
Its totient is φ = 25428746560.
The previous prime is 25564492319. The next prime is 25564492363. The reversal of 25564492321 is 12329446552.
The square root of 25564492321 is 159889.
It is a perfect power (a square), and thus also a powerful number.
It can be written as a sum of positive squares in 4 ways, for example, as 890365921 + 24674126400 = 29839^2 + 157080^2
It is not a de Polignac number, because 25564492321 - 21 = 25564492319 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (25564499321) 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 8 ways as a sum of consecutive naturals, for example, 44928525 + ... + 44929093.
Almost surely, 225564492321 is an apocalyptic number.
25564492321 is the 159889-th square number.
25564492321 is the 79945-th centered octagonal number.
It is an amenable number.
25564492321 is a deficient number, since it is larger than the sum of its proper divisors (136469112).
25564492321 is an frugal number, since it uses more digits than its factorization.
25564492321 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1700 (or 850 counting only the distinct ones).
The product of its digits is 518400, while the sum is 43.
The spelling of 25564492321 in words is "twenty-five billion, five hundred sixty-four million, four hundred ninety-two thousand, three hundred twenty-one".