987961954561 has 2 divisors, whose sum is σ = 987961954562. Its totient is φ = 987961954560.

The previous prime is 987961954559. The next prime is 987961954607. The reversal of 987961954561 is 165459169789.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 688568040000 + 299393914561 = 829800^2 + 547169^2 .

It is a cyclic number.

It is not a de Polignac number, because 987961954561 - 2¹ = 987961954559 is a prime.

Together with 987961954559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (987961954531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 493980977280 + 493980977281.

It is an arithmetic number, because the mean of its divisors is an integer number (493980977281).

Almost surely, 2^987961954561 is an apocalyptic number.

It is an amenable number.

987961954561 is a deficient number, since it is larger than the sum of its proper divisors (1).

987961954561 is an equidigital number, since it uses as much as digits as its factorization.

987961954561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 146966400, while the sum is 70.

The spelling of 987961954561 in words is "nine hundred eighty-seven billion, nine hundred sixty-one million, nine hundred fifty-four thousand, five hundred sixty-one".