7870721 has 2 divisors, whose sum is σ = 7870722. Its totient is φ = 7870720.

The previous prime is 7870717. The next prime is 7870739. The reversal of 7870721 is 1270787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7230721 + 640000 = 2689^2 + 800^2 .

It is a cyclic number.

It is not a de Polignac number, because 7870721 - 2² = 7870717 is a prime.

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

It is not a weakly prime, because it can be changed into another prime (7870321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3935360 + 3935361.

It is an arithmetic number, because the mean of its divisors is an integer number (3935361).

Almost surely, 2^7870721 is an apocalyptic number.

It is an amenable number.

7870721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7870721 is an equidigital number, since it uses as much as digits as its factorization.

7870721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5488, while the sum is 32.

The square root of 7870721 is about 2805.4805292498. The cubic root of 7870721 is about 198.9168191873.

The spelling of 7870721 in words is "seven million, eight hundred seventy thousand, seven hundred twenty-one".