87091989 has 16 divisors (see below), whose sum is σ = 120520704. Its totient is φ = 55882800.

The previous prime is 87091973. The next prime is 87091999. The reversal of 87091989 is 98919078.

It is not a de Polignac number, because 87091989 - 2⁴ = 87091973 is a prime.

It is a super-2 number, since 2×87091989² = 15170029095952242, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87091919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15312 + ... + 20214.

It is an arithmetic number, because the mean of its divisors is an integer number (7532544).

Almost surely, 2^87091989 is an apocalyptic number.

It is an amenable number.

87091989 is a deficient number, since it is larger than the sum of its proper divisors (33428715).

87091989 is a wasteful number, since it uses less digits than its factorization.

87091989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5128.

The product of its (nonzero) digits is 326592, while the sum is 51.

The square root of 87091989 is about 9332.3088783002. The cubic root of 87091989 is about 443.2608786687.

The spelling of 87091989 in words is "eighty-seven million, ninety-one thousand, nine hundred eighty-nine".