25685416649 has 2 divisors, whose sum is σ = 25685416650. Its totient is φ = 25685416648.

The previous prime is 25685416639. The next prime is 25685416663. The reversal of 25685416649 is 94661458652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20233071049 + 5452345600 = 142243^2 + 73840^2 .

It is a cyclic number.

It is not a de Polignac number, because 25685416649 - 2²⁴ = 25668639433 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 25685416594 and 25685416603.

It is not a weakly prime, because it can be changed into another prime (25685416619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12842708324 + 12842708325.

It is an arithmetic number, because the mean of its divisors is an integer number (12842708325).

Almost surely, 2^25685416649 is an apocalyptic number.

It is an amenable number.

25685416649 is a deficient number, since it is larger than the sum of its proper divisors (1).

25685416649 is an equidigital number, since it uses as much as digits as its factorization.

25685416649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12441600, while the sum is 56.

The spelling of 25685416649 in words is "twenty-five billion, six hundred eighty-five million, four hundred sixteen thousand, six hundred forty-nine".