981532561 has 2 divisors, whose sum is σ = 981532562. Its totient is φ = 981532560.

The previous prime is 981532549. The next prime is 981532619. The reversal of 981532561 is 165235189.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 819734161 + 161798400 = 28631^2 + 12720^2 .

It is a cyclic number.

It is not a de Polignac number, because 981532561 - 2⁵ = 981532529 is a prime.

It is not a weakly prime, because it can be changed into another prime (981532361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 490766280 + 490766281.

It is an arithmetic number, because the mean of its divisors is an integer number (490766281).

Almost surely, 2^981532561 is an apocalyptic number.

It is an amenable number.

981532561 is a deficient number, since it is larger than the sum of its proper divisors (1).

981532561 is an equidigital number, since it uses as much as digits as its factorization.

981532561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64800, while the sum is 40.

The square root of 981532561 is about 31329.4200552771. The cubic root of 981532561 is about 993.8058993330.

The spelling of 981532561 in words is "nine hundred eighty-one million, five hundred thirty-two thousand, five hundred sixty-one".