87790121 has 2 divisors, whose sum is σ = 87790122. Its totient is φ = 87790120.

The previous prime is 87790069. The next prime is 87790123. The reversal of 87790121 is 12109778.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87684496 + 105625 = 9364^2 + 325^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87790121 is a prime.

It is a Sophie Germain prime.

Together with 87790123, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (87790123) 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, 43895060 + 43895061.

It is an arithmetic number, because the mean of its divisors is an integer number (43895061).

Almost surely, 2^87790121 is an apocalyptic number.

It is an amenable number.

87790121 is a deficient number, since it is larger than the sum of its proper divisors (1).

87790121 is an equidigital number, since it uses as much as digits as its factorization.

87790121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 87790121 is about 9369.6382534226. The cubic root of 87790121 is about 444.4421254717.

Adding to 87790121 its reverse (12109778), we get a palindrome (99899899).

The spelling of 87790121 in words is "eighty-seven million, seven hundred ninety thousand, one hundred twenty-one".