2780505 has 72 divisors (see below), whose sum is σ = 6099912. Its totient is φ = 1161216.

The previous prime is 2780501. The next prime is 2780507. The reversal of 2780505 is 5050872.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 28224 + 2752281 = 168^2 + 1659^2 .

It is not a de Polignac number, because 2780505 - 2² = 2780501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2780501) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 28617 + ... + 28713.

It is an arithmetic number, because the mean of its divisors is an integer number (84721).

2^2780505 is an apocalyptic number.

It is an amenable number.

2780505 is an abundant number, since it is smaller than the sum of its proper divisors (3319407).

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

2780505 is a wasteful number, since it uses less digits than its factorization.

2780505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 125 counting only the distinct ones).

The product of its (nonzero) digits is 2800, while the sum is 27.

The square root of 2780505 is about 1667.4846326128. The cubic root of 2780505 is about 140.6181004022.

The spelling of 2780505 in words is "two million, seven hundred eighty thousand, five hundred five".