87835721 has 2 divisors, whose sum is σ = 87835722. Its totient is φ = 87835720.

The previous prime is 87835703. The next prime is 87835723. The reversal of 87835721 is 12753878.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87703225 + 132496 = 9365^2 + 364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87835721 is a prime.

It is a super-2 number, since 2×87835721² = 15430227767179682, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 87835723, 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 (87835723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43917860 + 43917861.

It is an arithmetic number, because the mean of its divisors is an integer number (43917861).

Almost surely, 2^87835721 is an apocalyptic number.

It is an amenable number.

87835721 is a deficient number, since it is larger than the sum of its proper divisors (1).

87835721 is an equidigital number, since it uses as much as digits as its factorization.

87835721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 94080, while the sum is 41.

The square root of 87835721 is about 9372.0713292207. The cubic root of 87835721 is about 444.5190629553.

The spelling of 87835721 in words is "eighty-seven million, eight hundred thirty-five thousand, seven hundred twenty-one".