2778660 has 72 divisors (see below), whose sum is σ = 8648640. Its totient is φ = 721728.

The previous prime is 2778649. The next prime is 2778673. The reversal of 2778660 is 668772.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7561 + ... + 7919.

It is an arithmetic number, because the mean of its divisors is an integer number (120120).

2^2778660 is an apocalyptic number.

2778660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2778660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4324320).

2778660 is an abundant number, since it is smaller than the sum of its proper divisors (5869980).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2778660 is a wasteful number, since it uses less digits than its factorization.

2778660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417 (or 412 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The square root of 2778660 is about 1666.9313123221. The cubic root of 2778660 is about 140.5869912092.

It can be divided in two parts, 27 and 78660, that added together give a palindrome (78687).

The spelling of 2778660 in words is "two million, seven hundred seventy-eight thousand, six hundred sixty".