87888721 has 2 divisors, whose sum is σ = 87888722. Its totient is φ = 87888720.

The previous prime is 87888683. The next prime is 87888733. The reversal of 87888721 is 12788878.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87142225 + 746496 = 9335^2 + 864^2 .

It is a cyclic number.

It is not a de Polignac number, because 87888721 - 2²¹ = 85791569 is a prime.

It is not a weakly prime, because it can be changed into another prime (87888761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43944360 + 43944361.

It is an arithmetic number, because the mean of its divisors is an integer number (43944361).

Almost surely, 2^87888721 is an apocalyptic number.

It is an amenable number.

87888721 is a deficient number, since it is larger than the sum of its proper divisors (1).

87888721 is an equidigital number, since it uses as much as digits as its factorization.

87888721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 401408, while the sum is 49.

The square root of 87888721 is about 9374.8984527834. The cubic root of 87888721 is about 444.6084524544.

The spelling of 87888721 in words is "eighty-seven million, eight hundred eighty-eight thousand, seven hundred twenty-one".