28777989 has 8 divisors (see below), whose sum is σ = 40390240. Its totient is φ = 18175536.

The previous prime is 28777981. The next prime is 28777997. The reversal of 28777989 is 98977782.

It is an interprime number because it is at equal distance from previous prime (28777981) and next prime (28777997).

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

It is not a de Polignac number, because 28777989 - 2³ = 28777981 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57), and also a Moran number because the ratio is a prime number: 504877 = 28777989 / (2 + 8 + 7 + 7 + 7 + 9 + 8 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28777981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 252382 + ... + 252495.

It is an arithmetic number, because the mean of its divisors is an integer number (5048780).

Almost surely, 2^28777989 is an apocalyptic number.

It is an amenable number.

28777989 is a deficient number, since it is larger than the sum of its proper divisors (11612251).

28777989 is a wasteful number, since it uses less digits than its factorization.

28777989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504899.

The product of its digits is 3556224, while the sum is 57.

The square root of 28777989 is about 5364.5120001730. The cubic root of 28777989 is about 306.4456639954.

The spelling of 28777989 in words is "twenty-eight million, seven hundred seventy-seven thousand, nine hundred eighty-nine".