87281221 has 2 divisors, whose sum is σ = 87281222. Its totient is φ = 87281220.

The previous prime is 87281219. The next prime is 87281267. The reversal of 87281221 is 12218278.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 85562500 + 1718721 = 9250^2 + 1311^2 .

It is a cyclic number.

It is not a de Polignac number, because 87281221 - 2¹ = 87281219 is a prime.

Together with 87281219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87281521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43640610 + 43640611.

It is an arithmetic number, because the mean of its divisors is an integer number (43640611).

Almost surely, 2^87281221 is an apocalyptic number.

It is an amenable number.

87281221 is a deficient number, since it is larger than the sum of its proper divisors (1).

87281221 is an equidigital number, since it uses as much as digits as its factorization.

87281221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3584, while the sum is 31.

The square root of 87281221 is about 9342.4419184708. The cubic root of 87281221 is about 443.5816830136.

Adding to 87281221 its reverse (12218278), we get a palindrome (99499499).

The spelling of 87281221 in words is "eighty-seven million, two hundred eighty-one thousand, two hundred twenty-one".