1025687561 has 2 divisors, whose sum is σ = 1025687562. Its totient is φ = 1025687560.

The previous prime is 1025687501. The next prime is 1025687587. The reversal of 1025687561 is 1657865201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 757350400 + 268337161 = 27520^2 + 16381^2 .

It is an emirp because it is prime and its reverse (1657865201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1025687561 - 2⁶ = 1025687497 is a prime.

It is not a weakly prime, because it can be changed into another prime (1025687501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 512843780 + 512843781.

It is an arithmetic number, because the mean of its divisors is an integer number (512843781).

Almost surely, 2^1025687561 is an apocalyptic number.

It is an amenable number.

1025687561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1025687561 is an equidigital number, since it uses as much as digits as its factorization.

1025687561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100800, while the sum is 41.

The square root of 1025687561 is about 32026.3572858357. The cubic root of 1025687561 is about 1008.4902322856.

The spelling of 1025687561 in words is "one billion, twenty-five million, six hundred eighty-seven thousand, five hundred sixty-one".