3870721 has 2 divisors, whose sum is σ = 3870722. Its totient is φ = 3870720.

The previous prime is 3870719. The next prime is 3870751. The reversal of 3870721 is 1270783.

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., 2283121 + 1587600 = 1511^2 + 1260^2 .

It is a cyclic number.

It is not a de Polignac number, because 3870721 - 2¹ = 3870719 is a prime.

Together with 3870719, it forms a pair of twin primes.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 3870721.

It is not a weakly prime, because it can be changed into another prime (3870751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1935360 + 1935361.

It is an arithmetic number, because the mean of its divisors is an integer number (1935361).

It is a Proth number, since it is equal to 945 ⋅ 2¹² + 1 and 945 < 2¹².

Almost surely, 2^3870721 is an apocalyptic number.

It is an amenable number.

3870721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3870721 is an equidigital number, since it uses as much as digits as its factorization.

3870721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 3870721 is about 1967.4148012049. The cubic root of 3870721 is about 157.0111964103.

The spelling of 3870721 in words is "three million, eight hundred seventy thousand, seven hundred twenty-one".