87638781 has 8 divisors (see below), whose sum is σ = 117019360. Its totient is φ = 58342032.

The previous prime is 87638753. The next prime is 87638797. The reversal of 87638781 is 18783678.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 87638781 - 2⁷ = 87638653 is a prime.

It is a super-2 number, since 2×87638781² = 15361111870331922, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 87638781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87638711) 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, 18475 + ... + 22728.

It is an arithmetic number, because the mean of its divisors is an integer number (14627420).

Almost surely, 2^87638781 is an apocalyptic number.

It is an amenable number.

87638781 is a deficient number, since it is larger than the sum of its proper divisors (29380579).

87638781 is a wasteful number, since it uses less digits than its factorization.

87638781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41915.

The product of its digits is 451584, while the sum is 48.

The square root of 87638781 is about 9361.5586843218. The cubic root of 87638781 is about 444.1865896623.

The spelling of 87638781 in words is "eighty-seven million, six hundred thirty-eight thousand, seven hundred eighty-one".