87878989 has 16 divisors (see below), whose sum is σ = 98086464. Its totient is φ = 78064000.

The previous prime is 87878981. The next prime is 87879041. The reversal of 87878989 is 98987878.

87878989 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is a cyclic number.

It is not a de Polignac number, because 87878989 - 2³ = 87878981 is a prime.

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 87878989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87878981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91737 + ... + 92689.

It is an arithmetic number, because the mean of its divisors is an integer number (6130404).

Almost surely, 2^87878989 is an apocalyptic number.

It is an amenable number.

87878989 is a deficient number, since it is larger than the sum of its proper divisors (10207475).

87878989 is a wasteful number, since it uses less digits than its factorization.

87878989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1148.

The product of its digits is 16257024, while the sum is 64.

The square root of 87878989 is about 9374.3793927918. The cubic root of 87878989 is about 444.5920412126.

Subtracting 87878989 from its reverse (98987878), we obtain a square (11108889 = 3333²).

It can be divided in two parts, 878789 and 89, that added together give a palindrome (878878).

The spelling of 87878989 in words is "eighty-seven million, eight hundred seventy-eight thousand, nine hundred eighty-nine".