2780400 has 120 divisors (see below), whose sum is σ = 10209664. Its totient is φ = 633600.

The previous prime is 2780399. The next prime is 2780413. The reversal of 2780400 is 40872.

It is a happy number.

2780400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8235 + ... + 8565.

2^2780400 is an apocalyptic number.

2780400 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 2780400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5104832).

2780400 is an abundant number, since it is smaller than the sum of its proper divisors (7429264).

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

2780400 is a wasteful number, since it uses less digits than its factorization.

2780400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359 (or 348 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 2780400 is about 1667.4531477676. The cubic root of 2780400 is about 140.6163303297.

The spelling of 2780400 in words is "two million, seven hundred eighty thousand, four hundred".