1631825561 has 2 divisors, whose sum is σ = 1631825562. Its totient is φ = 1631825560.

The previous prime is 1631825557. The next prime is 1631825609. The reversal of 1631825561 is 1655281361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1424609536 + 207216025 = 37744^2 + 14395^2 .

It is a cyclic number.

It is not a de Polignac number, because 1631825561 - 2² = 1631825557 is a prime.

It is not a weakly prime, because it can be changed into another prime (1631825521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 815912780 + 815912781.

It is an arithmetic number, because the mean of its divisors is an integer number (815912781).

Almost surely, 2^1631825561 is an apocalyptic number.

It is an amenable number.

1631825561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1631825561 is an equidigital number, since it uses as much as digits as its factorization.

1631825561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43200, while the sum is 38.

The square root of 1631825561 is about 40395.8606914124. The cubic root of 1631825561 is about 1177.3111141102.

The spelling of 1631825561 in words is "one billion, six hundred thirty-one million, eight hundred twenty-five thousand, five hundred sixty-one".