2780389 has 4 divisors (see below), whose sum is σ = 2792556. Its totient is φ = 2768224.

The previous prime is 2780369. The next prime is 2780399. The reversal of 2780389 is 9830872.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1476225 + 1304164 = 1215^2 + 1142^2 .

It is a cyclic number.

It is not a de Polignac number, because 2780389 - 2⁵ = 2780357 is a prime.

It is a Duffinian number.

2780389 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2780329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5734 + ... + 6199.

It is an arithmetic number, because the mean of its divisors is an integer number (698139).

2^2780389 is an apocalyptic number.

It is an amenable number.

2780389 is a deficient number, since it is larger than the sum of its proper divisors (12167).

2780389 is a wasteful number, since it uses less digits than its factorization.

2780389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12166.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 2780389 is about 1667.4498493208. The cubic root of 2780389 is about 140.6161448910.

The spelling of 2780389 in words is "two million, seven hundred eighty thousand, three hundred eighty-nine".