1987650884761 has 2 divisors, whose sum is σ = 1987650884762. Its totient is φ = 1987650884760.

The previous prime is 1987650884753. The next prime is 1987650884881. The reversal of 1987650884761 is 1674880567891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1781207875161 + 206443009600 = 1334619^2 + 454360^2 .

It is an emirp because it is prime and its reverse (1674880567891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1987650884761 - 2³ = 1987650884753 is a prime.

It is a super-2 number, since 2×1987650884761² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1987650884731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993825442380 + 993825442381.

It is an arithmetic number, because the mean of its divisors is an integer number (993825442381).

Almost surely, 2^{1987650884761} is an apocalyptic number.

It is an amenable number.

1987650884761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987650884761 is an equidigital number, since it uses as much as digits as its factorization.

1987650884761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162570240, while the sum is 70.

The spelling of 1987650884761 in words is "one trillion, nine hundred eighty-seven billion, six hundred fifty million, eight hundred eighty-four thousand, seven hundred sixty-one".