25561601 has 8 divisors (see below), whose sum is σ = 27838440. Its totient is φ = 23329152.

The previous prime is 25561559. The next prime is 25561603. The reversal of 25561601 is 10616552.

It can be written as a sum of positive squares in 4 ways, for example, as 1893376 + 23668225 = 1376^2 + 4865^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25561601 is a prime.

It is a super-3 number, since 3×25561601³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25561603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9890 + ... + 12203.

It is an arithmetic number, because the mean of its divisors is an integer number (3479805).

Almost surely, 2^25561601 is an apocalyptic number.

It is an amenable number.

25561601 is a deficient number, since it is larger than the sum of its proper divisors (2276839).

25561601 is a wasteful number, since it uses less digits than its factorization.

25561601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22195.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 25561601 is about 5055.8481978794. The cubic root of 25561601 is about 294.5750887306.

It can be divided in two parts, 25561 and 601, that added together give a palindrome (26162).

The spelling of 25561601 in words is "twenty-five million, five hundred sixty-one thousand, six hundred one".