2778940 has 48 divisors (see below), whose sum is σ = 6289920. Its totient is φ = 1028160.

The previous prime is 2778917. The next prime is 2778967. The reversal of 2778940 is 498772.

2778940 = T₆₇ + T₆₈ + ... + T₂₅₆.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 2778940.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26929 + ... + 27031.

It is an arithmetic number, because the mean of its divisors is an integer number (131040).

2^2778940 is an apocalyptic number.

2778940 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 2778940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3144960).

2778940 is an abundant number, since it is smaller than the sum of its proper divisors (3510980).

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

2778940 is a wasteful number, since it uses less digits than its factorization.

2778940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202 (or 200 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 2778940 is about 1667.0152968704. The cubic root of 2778940 is about 140.5917132737.

Subtracting from 2778940 its sum of digits (37), we obtain a triangular number (2778903 = T₂₃₅₇).

The spelling of 2778940 in words is "two million, seven hundred seventy-eight thousand, nine hundred forty".