87211989 has 12 divisors (see below), whose sum is σ = 133383276. Its totient is φ = 54721152.

The previous prime is 87211981. The next prime is 87211991. The reversal of 87211989 is 98911278.

It can be written as a sum of positive squares in 2 ways, for example, as 46991025 + 40220964 = 6855^2 + 6342^2 .

It is not a de Polignac number, because 87211989 - 2³ = 87211981 is a prime.

It is a super-2 number, since 2×87211989² = 15211862050672242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87211981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 284854 + ... + 285159.

It is an arithmetic number, because the mean of its divisors is an integer number (11115273).

Almost surely, 2^87211989 is an apocalyptic number.

It is an amenable number.

87211989 is a deficient number, since it is larger than the sum of its proper divisors (46171287).

87211989 is a wasteful number, since it uses less digits than its factorization.

87211989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570036 (or 570033 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 87211989 is about 9338.7359422997. The cubic root of 87211989 is about 443.4643680857.

The spelling of 87211989 in words is "eighty-seven million, two hundred eleven thousand, nine hundred eighty-nine".