84778989 has 16 divisors (see below), whose sum is σ = 119066112. Its totient is φ = 53552048.

The previous prime is 84778987. The next prime is 84779003. The reversal of 84778989 is 98987748.

It is a cyclic number.

It is not a de Polignac number, because 84778989 - 2¹ = 84778987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84778987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1642 + ... + 13124.

It is an arithmetic number, because the mean of its divisors is an integer number (7441632).

Almost surely, 2^84778989 is an apocalyptic number.

84778989 is the 4922-nd nonagonal number.

It is an amenable number.

84778989 is a deficient number, since it is larger than the sum of its proper divisors (34287123).

84778989 is a wasteful number, since it uses less digits than its factorization.

84778989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11616.

The product of its digits is 8128512, while the sum is 60.

The square root of 84778989 is about 9207.5506515034. The cubic root of 84778989 is about 439.3015589159.

The spelling of 84778989 in words is "eighty-four million, seven hundred seventy-eight thousand, nine hundred eighty-nine".