87185391 has 4 divisors (see below), whose sum is σ = 116247192. Its totient is φ = 58123592.

The previous prime is 87185389. The next prime is 87185453. The reversal of 87185391 is 19358178.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 87185391 - 2¹ = 87185389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87185491) 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 3 ways as a sum of consecutive naturals, for example, 14530896 + ... + 14530901.

It is an arithmetic number, because the mean of its divisors is an integer number (29061798).

Almost surely, 2^87185391 is an apocalyptic number.

87185391 is a deficient number, since it is larger than the sum of its proper divisors (29061801).

87185391 is a wasteful number, since it uses less digits than its factorization.

87185391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29061800.

The product of its digits is 60480, while the sum is 42.

The square root of 87185391 is about 9337.3117651710. The cubic root of 87185391 is about 443.4192807656.

The spelling of 87185391 in words is "eighty-seven million, one hundred eighty-five thousand, three hundred ninety-one".