2789781 has 8 divisors (see below), whose sum is σ = 3739200. Its totient is φ = 1850112.

The previous prime is 2789777. The next prime is 2789791. The reversal of 2789781 is 1879872.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2789781 - 2² = 2789777 is a prime.

It is a super-2 number, since 2×2789781² = 15565756055922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

2789781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2789701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1740 + ... + 2933.

It is an arithmetic number, because the mean of its divisors is an integer number (467400).

2^2789781 is an apocalyptic number.

It is an amenable number.

2789781 is a deficient number, since it is larger than the sum of its proper divisors (949419).

2789781 is a wasteful number, since it uses less digits than its factorization.

2789781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4875.

The product of its digits is 56448, while the sum is 42.

The square root of 2789781 is about 1670.2637516273. The cubic root of 2789781 is about 140.7742981291.

Subtracting from 2789781 its reverse (1879872), we obtain a palindrome (909909).

It can be divided in two parts, 2789 and 781, that added together give a triangular number (3570 = T₈₄).

The spelling of 2789781 in words is "two million, seven hundred eighty-nine thousand, seven hundred eighty-one".