3847721 has 2 divisors, whose sum is σ = 3847722. Its totient is φ = 3847720.

The previous prime is 3847687. The next prime is 3847777. The reversal of 3847721 is 1277483.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3463321 + 384400 = 1861^2 + 620^2 .

It is an emirp because it is prime and its reverse (1277483) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3847721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (3847021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1923860 + 1923861.

It is an arithmetic number, because the mean of its divisors is an integer number (1923861).

Almost surely, 2^3847721 is an apocalyptic number.

It is an amenable number.

3847721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3847721 is an equidigital number, since it uses as much as digits as its factorization.

3847721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9408, while the sum is 32.

The square root of 3847721 is about 1961.5608580924. The cubic root of 3847721 is about 156.6995891778.

The spelling of 3847721 in words is "three million, eight hundred forty-seven thousand, seven hundred twenty-one".