3646721 has 16 divisors (see below), whose sum is σ = 4309200. Its totient is φ = 3053568.

The previous prime is 3646717. The next prime is 3646723. The reversal of 3646721 is 1276463.

It can be written as a sum of positive squares in 8 ways, for example, as 172225 + 3474496 = 415^2 + 1864^2 .

It is a cyclic number.

It is not a de Polignac number, because 3646721 - 2² = 3646717 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

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 (3646723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6125 + ... + 6693.

It is an arithmetic number, because the mean of its divisors is an integer number (269325).

Almost surely, 2^3646721 is an apocalyptic number.

It is an amenable number.

3646721 is a deficient number, since it is larger than the sum of its proper divisors (662479).

3646721 is a wasteful number, since it uses less digits than its factorization.

3646721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 628.

The product of its digits is 6048, while the sum is 29.

The square root of 3646721 is about 1909.6389711147. The cubic root of 3646721 is about 153.9220525306.

The spelling of 3646721 in words is "three million, six hundred forty-six thousand, seven hundred twenty-one".