25566649 has 2 divisors, whose sum is σ = 25566650. Its totient is φ = 25566648.

The previous prime is 25566641. The next prime is 25566677. The reversal of 25566649 is 94666552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16000000 + 9566649 = 4000^2 + 3093^2 .

It is a cyclic number.

It is not a de Polignac number, because 25566649 - 2³ = 25566641 is a prime.

It is not a weakly prime, because it can be changed into another prime (25566641) 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, 12783324 + 12783325.

It is an arithmetic number, because the mean of its divisors is an integer number (12783325).

Almost surely, 2^25566649 is an apocalyptic number.

It is an amenable number.

25566649 is a deficient number, since it is larger than the sum of its proper divisors (1).

25566649 is an equidigital number, since it uses as much as digits as its factorization.

25566649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 388800, while the sum is 43.

The square root of 25566649 is about 5056.3473970842. The cubic root of 25566649 is about 294.5944787155.

The spelling of 25566649 in words is "twenty-five million, five hundred sixty-six thousand, six hundred forty-nine".