25261661 has 2 divisors, whose sum is σ = 25261662. Its totient is φ = 25261660.

The previous prime is 25261603. The next prime is 25261673. The reversal of 25261661 is 16616252.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22146436 + 3115225 = 4706^2 + 1765^2 .

It is a cyclic number.

It is not a de Polignac number, because 25261661 - 2¹⁰ = 25260637 is a prime.

It is equal to p_1581194 and since 25261661 and 1581194 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25261681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12630830 + 12630831.

It is an arithmetic number, because the mean of its divisors is an integer number (12630831).

Almost surely, 2^25261661 is an apocalyptic number.

It is an amenable number.

25261661 is a deficient number, since it is larger than the sum of its proper divisors (1).

25261661 is an equidigital number, since it uses as much as digits as its factorization.

25261661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 29.

The square root of 25261661 is about 5026.0979894944. The cubic root of 25261661 is about 293.4183705187.

It can be divided in two parts, 252616 and 61, that multiplied together give a triangular number (15409576 = T₅₅₅₁).

The spelling of 25261661 in words is "twenty-five million, two hundred sixty-one thousand, six hundred sixty-one".