87236640 has 144 divisors (see below), whose sum is σ = 308107800. Its totient is φ = 22450176.

The previous prime is 87236627. The next prime is 87236651. The reversal of 87236640 is 4663278.

87236640 is a `hidden beast` number, since 8 + 7 + 2 + 3 + 6 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 82519056 + 4717584 = 9084^2 + 2172^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×87236640² = 15220462716979200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 87236595 and 87236604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 40716 + ... + 42804.

Almost surely, 2^87236640 is an apocalyptic number.

87236640 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 87236640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154053900).

87236640 is an abundant number, since it is smaller than the sum of its proper divisors (220871160).

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

87236640 is a wasteful number, since it uses less digits than its factorization.

87236640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2139 (or 2128 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 87236640 is about 9340.0556743523. The cubic root of 87236640 is about 443.5061467847.

The spelling of 87236640 in words is "eighty-seven million, two hundred thirty-six thousand, six hundred forty".