2124781 has 4 divisors (see below), whose sum is σ = 2129632. Its totient is φ = 2119932.

The previous prime is 2124769. The next prime is 2124791. The reversal of 2124781 is 1874212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2124781 is a prime.

It is a super-2 number, since 2×2124781² = 9029388595922, which contains 22 as substring.

It is a Duffinian number.

2124781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2124761) 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, 1695 + ... + 2668.

It is an arithmetic number, because the mean of its divisors is an integer number (532408).

2^2124781 is an apocalyptic number.

It is an amenable number.

2124781 is a deficient number, since it is larger than the sum of its proper divisors (4851).

2124781 is an equidigital number, since it uses as much as digits as its factorization.

2124781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4850.

The product of its digits is 896, while the sum is 25.

The square root of 2124781 is about 1457.6628553956. The cubic root of 2124781 is about 128.5596628269.

Adding to 2124781 its reverse (1874212), we get a palindrome (3998993).

The spelling of 2124781 in words is "two million, one hundred twenty-four thousand, seven hundred eighty-one".