3888721 has 2 divisors, whose sum is σ = 3888722. Its totient is φ = 3888720.

The previous prime is 3888719. The next prime is 3888761. The reversal of 3888721 is 1278883.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3748096 + 140625 = 1936^2 + 375^2 .

It is a cyclic number.

It is not a de Polignac number, because 3888721 - 2¹ = 3888719 is a prime.

Together with 3888719, it forms a pair of twin primes.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (3888761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1944360 + 1944361.

It is an arithmetic number, because the mean of its divisors is an integer number (1944361).

Almost surely, 2^3888721 is an apocalyptic number.

It is an amenable number.

3888721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3888721 is an equidigital number, since it uses as much as digits as its factorization.

3888721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 37.

The square root of 3888721 is about 1971.9840263045. The cubic root of 3888721 is about 157.2542029826.

The spelling of 3888721 in words is "three million, eight hundred eighty-eight thousand, seven hundred twenty-one".