87636221 has 2 divisors, whose sum is σ = 87636222. Its totient is φ = 87636220.

The previous prime is 87636203. The next prime is 87636259. The reversal of 87636221 is 12263678.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50608996 + 37027225 = 7114^2 + 6085^2 .

It is a cyclic number.

It is not a de Polignac number, because 87636221 - 2¹⁴ = 87619837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87636821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43818110 + 43818111.

It is an arithmetic number, because the mean of its divisors is an integer number (43818111).

Almost surely, 2^87636221 is an apocalyptic number.

It is an amenable number.

87636221 is a deficient number, since it is larger than the sum of its proper divisors (1).

87636221 is an equidigital number, since it uses as much as digits as its factorization.

87636221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 35.

The square root of 87636221 is about 9361.4219539555. The cubic root of 87636221 is about 444.1822646031.

Adding to 87636221 its reverse (12263678), we get a palindrome (99899899).

The spelling of 87636221 in words is "eighty-seven million, six hundred thirty-six thousand, two hundred twenty-one".