3318721 has 12 divisors (see below), whose sum is σ = 3909060.
Its totient is φ = 2808960.
The previous prime is 3318719. The next prime is 3318769. The reversal of 3318721 is 1278133.
It can be written as a sum of positive squares in 2 ways, for example, as 207025 + 3111696 = 455^2 + 1764^2
It is not a de Polignac number, because 3318721 - 21 = 3318719 is a prime.
It is a super-2 number, since 2×33187212 = 22027818151682, which contains 22 as substring.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (3318221) by changing a digit.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3981 + ... + 4741.
It is an arithmetic number, because the mean of its divisors is an integer number (325755).
Almost surely, 23318721 is an apocalyptic number.
It is an amenable number.
3318721 is a deficient number, since it is larger than the sum of its proper divisors (590339).
3318721 is an equidigital number, since it uses as much as digits as its factorization.
With its successor (3318722) it forms an eRAP, since the sums of their prime factors are consecutive (864 and 865).
3318721 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 864 (or 857 counting only the distinct ones).
The product of its digits is 1008, while the sum is 25.
The square root of 3318721 is about 1821.7357107989.
The cubic root of 3318721 is about 149.1615592160.
The spelling of 3318721 in words is "three million, three hundred eighteen thousand, seven hundred twenty-one".