87007721 has 2 divisors, whose sum is σ = 87007722. Its totient is φ = 87007720.

The previous prime is 87007703. The next prime is 87007727. The reversal of 87007721 is 12770078.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79852096 + 7155625 = 8936^2 + 2675^2 .

It is a cyclic number.

It is not a de Polignac number, because 87007721 - 2¹⁴ = 86991337 is a prime.

It is a super-2 number, since 2×87007721² = 15140687027227682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (87007727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43503860 + 43503861.

It is an arithmetic number, because the mean of its divisors is an integer number (43503861).

Almost surely, 2^87007721 is an apocalyptic number.

It is an amenable number.

87007721 is a deficient number, since it is larger than the sum of its proper divisors (1).

87007721 is an equidigital number, since it uses as much as digits as its factorization.

87007721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5488, while the sum is 32.

The square root of 87007721 is about 9327.7929329504. The cubic root of 87007721 is about 443.1178698731.

Adding to 87007721 its reverse (12770078), we get a palindrome (99777799).

The spelling of 87007721 in words is "eighty-seven million, seven thousand, seven hundred twenty-one".