3688721 has 8 divisors (see below), whose sum is σ = 3830784. Its totient is φ = 3548160.

The previous prime is 3688709. The next prime is 3688757. The reversal of 3688721 is 1278863.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3688721 is a prime.

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 (3688781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7736 + ... + 8198.

It is an arithmetic number, because the mean of its divisors is an integer number (478848).

Almost surely, 2^3688721 is an apocalyptic number.

3688721 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

3688721 is a deficient number, since it is larger than the sum of its proper divisors (142063).

3688721 is a wasteful number, since it uses less digits than its factorization.

3688721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 751.

The product of its digits is 16128, while the sum is 35.

The square root of 3688721 is about 1920.6043319747. The cubic root of 3688721 is about 154.5107151759.

The spelling of 3688721 in words is "three million, six hundred eighty-eight thousand, seven hundred twenty-one".