2778889 has 3 divisors (see below), whose sum is σ = 2780557.
Its totient is φ = 2777222.
The previous prime is 2778877. The next prime is 2778901. The reversal of 2778889 is 9888772.
Multipling 2778889 by its sum of digits (49), we get a square (136165561 = 116692).
Multipling 2778889 by its product of digits (451584), we get a square (1254901810176 = 11202242).
It can be divided in two parts, 2778 and 889, that multiplied together give a palindrome (2469642).
The square root of 2778889 is 1667.
It is a perfect power (a square), and thus also a powerful number.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.
It is an interprime number because it is at equal distance from previous prime (2778877) and next prime (2778901).
It is not a de Polignac number, because 2778889 - 211 = 2776841 is a prime.
It is a d-powerful number, because it can be written as 217 + 74 + 75 + 8 + 8 + 87 + 96 .
It is a Duffinian number.
2778889 is a lucky number.
It is a plaindrome in base 10.
It is not an unprimeable number, because it can be changed into a prime (2778829) by changing a digit.
It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 834 + ... + 2500.
22778889 is an apocalyptic number.
2778889 is the 1667-th square number.
2778889 is the 834-th centered octagonal number.
It is an amenable number.
2778889 is a deficient number, since it is larger than the sum of its proper divisors (1668).
2778889 is an frugal number, since it uses more digits than its factorization.
2778889 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 3334 (or 1667 counting only the distinct ones).
The product of its digits is 451584, while the sum is 49.
The cubic root of 2778889 is about 140.5908532070.
The spelling of 2778889 in words is "two million, seven hundred seventy-eight thousand, eight hundred eighty-nine".