87639840 has 96 divisors (see below), whose sum is σ = 306754560. Its totient is φ = 23369472.

The previous prime is 87639829. The next prime is 87639847. The reversal of 87639840 is 4893678.

It is a happy number.

87639840 is a `hidden beast` number, since 8 + 7 + 639 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87639847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5824 + ... + 14463.

It is an arithmetic number, because the mean of its divisors is an integer number (3195360).

Almost surely, 2^87639840 is an apocalyptic number.

87639840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

87639840 is an abundant number, since it is smaller than the sum of its proper divisors (219114720).

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

87639840 is a wasteful number, since it uses less digits than its factorization.

87639840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20311 (or 20297 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 87639840 is about 9361.6152452448. The cubic root of 87639840 is about 444.1883787930.

The spelling of 87639840 in words is "eighty-seven million, six hundred thirty-nine thousand, eight hundred forty".