2231781 has 8 divisors (see below), whose sum is σ = 2987040. Its totient is φ = 1482192.

The previous prime is 2231773. The next prime is 2231791. The reversal of 2231781 is 1871322.

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

It is not a de Polignac number, because 2231781 - 2³ = 2231773 is a prime.

It is a super-3 number, since 3×2231781³ = 33348475292305057623, which contains 333 as substring. Note that it is a super-d number also for d = 2.

2231781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2231711) 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, 391 + ... + 2148.

It is an arithmetic number, because the mean of its divisors is an integer number (373380).

2^2231781 is an apocalyptic number.

It is an amenable number.

2231781 is a deficient number, since it is larger than the sum of its proper divisors (755259).

2231781 is a wasteful number, since it uses less digits than its factorization.

2231781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2835.

The product of its digits is 672, while the sum is 24.

The square root of 2231781 is about 1493.9146561969. The cubic root of 2231781 is about 130.6824271505.

The spelling of 2231781 in words is "two million, two hundred thirty-one thousand, seven hundred eighty-one".