2618721 has 24 divisors (see below), whose sum is σ = 4365504. Its totient is φ = 1481760.

The previous prime is 2618717. The next prime is 2618741. The reversal of 2618721 is 1278162.

It is not a de Polignac number, because 2618721 - 2² = 2618717 is a prime.

2618721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2618741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12306 + ... + 12516.

It is an arithmetic number, because the mean of its divisors is an integer number (181896).

2^2618721 is an apocalyptic number.

2618721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2618721 is a deficient number, since it is larger than the sum of its proper divisors (1746783).

2618721 is a wasteful number, since it uses less digits than its factorization.

2618721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421 (or 418 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 2618721 is about 1618.2462729758. The cubic root of 2618721 is about 137.8361318938.

The spelling of 2618721 in words is "two million, six hundred eighteen thousand, seven hundred twenty-one".