25009661 has 2 divisors, whose sum is σ = 25009662. Its totient is φ = 25009660.

The previous prime is 25009651. The next prime is 25009667. The reversal of 25009661 is 16690052.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24900100 + 109561 = 4990^2 + 331^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25009661 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25009667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12504830 + 12504831.

It is an arithmetic number, because the mean of its divisors is an integer number (12504831).

Almost surely, 2^25009661 is an apocalyptic number.

25009661 is the 2237-th centered decagonal number.

It is an amenable number.

25009661 is a deficient number, since it is larger than the sum of its proper divisors (1).

25009661 is an equidigital number, since it uses as much as digits as its factorization.

25009661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 25009661 is about 5000.9660066831. The cubic root of 25009661 is about 292.4394342177.

The spelling of 25009661 in words is "twenty-five million, nine thousand, six hundred sixty-one".