87840391 has 16 divisors (see below), whose sum is σ = 94464000. Its totient is φ = 81496800.

The previous prime is 87840373. The next prime is 87840461. The reversal of 87840391 is 19304878.

It is a cyclic number.

It is not a de Polignac number, because 87840391 - 2⁵ = 87840359 is a prime.

It is a super-3 number, since 3×87840391³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87840341) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 178656 + ... + 179146.

It is an arithmetic number, because the mean of its divisors is an integer number (5904000).

Almost surely, 2^87840391 is an apocalyptic number.

87840391 is a deficient number, since it is larger than the sum of its proper divisors (6623609).

87840391 is a wasteful number, since it uses less digits than its factorization.

87840391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 87840391 is about 9372.3204704065. The cubic root of 87840391 is about 444.5269407951.

The spelling of 87840391 in words is "eighty-seven million, eight hundred forty thousand, three hundred ninety-one".