87021988769 has 2 divisors, whose sum is σ = 87021988770. Its totient is φ = 87021988768.

The previous prime is 87021988741. The next prime is 87021988777. The reversal of 87021988769 is 96788912078.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54528321169 + 32493667600 = 233513^2 + 180260^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87021988769 is a prime.

It is a super-2 number, since 2×87021988769² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (87021928769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43510994384 + 43510994385.

It is an arithmetic number, because the mean of its divisors is an integer number (43510994385).

Almost surely, 2^87021988769 is an apocalyptic number.

It is an amenable number.

87021988769 is a deficient number, since it is larger than the sum of its proper divisors (1).

87021988769 is an equidigital number, since it uses as much as digits as its factorization.

87021988769 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24385536, while the sum is 65.

The spelling of 87021988769 in words is "eighty-seven billion, twenty-one million, nine hundred eighty-eight thousand, seven hundred sixty-nine".