87661440 has 320 divisors, whose sum is σ = 333234000. Its totient is φ = 21897216.

The previous prime is 87661373. The next prime is 87661447. The reversal of 87661440 is 4416678.

It is a tau number, because it is divible by the number of its divisors (320).

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 = 87661395 and 87661404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87661447) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 984916 + ... + 985004.

Almost surely, 2^87661440 is an apocalyptic number.

87661440 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 87661440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (166617000).

87661440 is an abundant number, since it is smaller than the sum of its proper divisors (245572560).

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

87661440 is a wasteful number, since it uses less digits than its factorization.

87661440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 118 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 87661440 is about 9362.7688212409. The cubic root of 87661440 is about 444.2248678329.

The spelling of 87661440 in words is "eighty-seven million, six hundred sixty-one thousand, four hundred forty".