2287781 has 4 divisors (see below), whose sum is σ = 2366700. Its totient is φ = 2208864.

The previous prime is 2287777. The next prime is 2287807. The reversal of 2287781 is 1877822.

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 410881 + 1876900 = 641^2 + 1370^2 .

It is a cyclic number.

It is not a de Polignac number, because 2287781 - 2² = 2287777 is a prime.

It is a super-2 number, since 2×2287781² = 10467883807922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2287381) 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, 39416 + ... + 39473.

It is an arithmetic number, because the mean of its divisors is an integer number (591675).

2^2287781 is an apocalyptic number.

It is an amenable number.

2287781 is a deficient number, since it is larger than the sum of its proper divisors (78919).

2287781 is an equidigital number, since it uses as much as digits as its factorization.

2287781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78918.

The product of its digits is 12544, while the sum is 35.

The square root of 2287781 is about 1512.5412391072. The cubic root of 2287781 is about 131.7664411356.

The spelling of 2287781 in words is "two million, two hundred eighty-seven thousand, seven hundred eighty-one".