87102021221 has 2 divisors, whose sum is σ = 87102021222. Its totient is φ = 87102021220.

The previous prime is 87102021191. The next prime is 87102021277. The reversal of 87102021221 is 12212020178.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47147608225 + 39954412996 = 217135^2 + 199886^2 .

It is a cyclic number.

It is not a de Polignac number, because 87102021221 - 2¹⁸ = 87101759077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87102021121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43551010610 + 43551010611.

It is an arithmetic number, because the mean of its divisors is an integer number (43551010611).

Almost surely, 2^87102021221 is an apocalyptic number.

It is an amenable number.

87102021221 is a deficient number, since it is larger than the sum of its proper divisors (1).

87102021221 is an equidigital number, since it uses as much as digits as its factorization.

87102021221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 26.

Adding to 87102021221 its reverse (12212020178), we get a palindrome (99314041399).

The spelling of 87102021221 in words is "eighty-seven billion, one hundred two million, twenty-one thousand, two hundred twenty-one".