87109840 has 40 divisors (see below), whose sum is σ = 208011240. Its totient is φ = 33901056.

The previous prime is 87109837. The next prime is 87109843. The reversal of 87109840 is 4890178.

It is an interprime number because it is at equal distance from previous prime (87109837) and next prime (87109843).

It can be written as a sum of positive squares in 4 ways, for example, as 45481536 + 41628304 = 6744^2 + 6452^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 87109840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87109843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11755 + ... + 17674.

It is an arithmetic number, because the mean of its divisors is an integer number (5200281).

Almost surely, 2^87109840 is an apocalyptic number.

87109840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

87109840 is an abundant number, since it is smaller than the sum of its proper divisors (120901400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

87109840 is a wasteful number, since it uses less digits than its factorization.

87109840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29479 (or 29473 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 87109840 is about 9333.2652378468. The cubic root of 87109840 is about 443.2911612450.

The spelling of 87109840 in words is "eighty-seven million, one hundred nine thousand, eight hundred forty".