87202021 has 2 divisors, whose sum is σ = 87202022. Its totient is φ = 87202020.

The previous prime is 87202019. The next prime is 87202051. The reversal of 87202021 is 12020278.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46049796 + 41152225 = 6786^2 + 6415^2 .

It is a cyclic number.

It is not a de Polignac number, because 87202021 - 2¹ = 87202019 is a prime.

Together with 87202019, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 87201983 and 87202001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87202051) 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, 43601010 + 43601011.

It is an arithmetic number, because the mean of its divisors is an integer number (43601011).

Almost surely, 2^87202021 is an apocalyptic number.

It is an amenable number.

87202021 is a deficient number, since it is larger than the sum of its proper divisors (1).

87202021 is an equidigital number, since it uses as much as digits as its factorization.

87202021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 87202021 is about 9338.2022359767. The cubic root of 87202021 is about 443.4474720094.

Adding to 87202021 its reverse (12020278), we get a palindrome (99222299).

The spelling of 87202021 in words is "eighty-seven million, two hundred two thousand, twenty-one".