3907721 has 12 divisors (see below), whose sum is σ = 4198020. Its totient is φ = 3632160.

The previous prime is 3907699. The next prime is 3907727. The reversal of 3907721 is 1277093.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 883600 + 3024121 = 940^2 + 1739^2 .

It is not a de Polignac number, because 3907721 - 2¹⁰ = 3906697 is a prime.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3907727) 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, 64031 + ... + 64091.

It is an arithmetic number, because the mean of its divisors is an integer number (349835).

Almost surely, 2^3907721 is an apocalyptic number.

It is an amenable number.

3907721 is a deficient number, since it is larger than the sum of its proper divisors (290299).

3907721 is an equidigital number, since it uses as much as digits as its factorization.

3907721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 2646, while the sum is 29.

The square root of 3907721 is about 1976.7956394124. The cubic root of 3907721 is about 157.5098977571.

The spelling of 3907721 in words is "three million, nine hundred seven thousand, seven hundred twenty-one".