25604581649409 has 189 divisors, whose sum is σ = 45842916732249. Its totient is φ = 14252471614080.

The previous prime is 25604581649401. The next prime is 25604581649417. The reversal of 25604581649409 is 90494618540652.

The square root of 25604581649409 is 5060097.

It is a perfect power (a square), and thus also a powerful number.

25604581649409 is a `hidden beast` number, since 2 + 5 + 6 + 0 + 4 + 581 + 6 + 4 + 9 + 40 + 9 = 666.

It is an interprime number because it is at equal distance from previous prime (25604581649401) and next prime (25604581649417).

It can be written as a sum of positive squares in 4 ways, for example, as 14352770135025 + 11251811514384 = 3788505^2 + 3354372^2 .

It is a tau number, because it is divible by the number of its divisors (189).

It is not a de Polignac number, because 25604581649409 - 2³ = 25604581649401 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (25604581649401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 188 ways as a sum of consecutive naturals, for example, 39210691327 + ... + 39210691979.

Almost surely, 2^{25604581649409} is an apocalyptic number.

25604581649409 is the 5060097-th square number.

25604581649409 is the 2530049-th centered octagonal number.

It is an amenable number.

25604581649409 is a deficient number, since it is larger than the sum of its proper divisors (20238335082840).

25604581649409 is an frugal number, since it uses more digits than its factorization.

25604581649409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1420 (or 704 counting only the distinct ones).

The product of its (nonzero) digits is 74649600, while the sum is 63.

The spelling of 25604581649409 in words is "twenty-five trillion, six hundred four billion, five hundred eighty-one million, six hundred forty-nine thousand, four hundred nine".