87820121 has 2 divisors, whose sum is σ = 87820122. Its totient is φ = 87820120.

The previous prime is 87820069. The next prime is 87820133. The reversal of 87820121 is 12102878.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73342096 + 14478025 = 8564^2 + 3805^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87820121 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (87820021) 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, 43910060 + 43910061.

It is an arithmetic number, because the mean of its divisors is an integer number (43910061).

Almost surely, 2^87820121 is an apocalyptic number.

It is an amenable number.

87820121 is a deficient number, since it is larger than the sum of its proper divisors (1).

87820121 is an equidigital number, since it uses as much as digits as its factorization.

87820121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 87820121 is about 9371.2390322732. The cubic root of 87820121 is about 444.4927452344.

Adding to 87820121 its reverse (12102878), we get a palindrome (99922999).

The spelling of 87820121 in words is "eighty-seven million, eight hundred twenty thousand, one hundred twenty-one".