3685721 has 12 divisors (see below), whose sum is σ = 4047228. Its totient is φ = 3354624.

The previous prime is 3685699. The next prime is 3685729. The reversal of 3685721 is 1275863.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 2088025 + 1597696 = 1445^2 + 1264^2 .

It is not a de Polignac number, because 3685721 - 2⁶ = 3685657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3685729) 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, 19001 + ... + 19193.

It is an arithmetic number, because the mean of its divisors is an integer number (337269).

Almost surely, 2^3685721 is an apocalyptic number.

It is an amenable number.

3685721 is a deficient number, since it is larger than the sum of its proper divisors (361507).

3685721 is a wasteful number, since it uses less digits than its factorization.

3685721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332 (or 319 counting only the distinct ones).

The product of its digits is 10080, while the sum is 32.

The square root of 3685721 is about 1919.8231689403. The cubic root of 3685721 is about 154.4688164740.

The spelling of 3685721 in words is "three million, six hundred eighty-five thousand, seven hundred twenty-one".