7869721 has 2 divisors, whose sum is σ = 7869722. Its totient is φ = 7869720.

The previous prime is 7869713. The next prime is 7869739. The reversal of 7869721 is 1279687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6579225 + 1290496 = 2565^2 + 1136^2 .

It is an emirp because it is prime and its reverse (1279687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7869721 - 2³ = 7869713 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (7869751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3934860 + 3934861.

It is an arithmetic number, because the mean of its divisors is an integer number (3934861).

Almost surely, 2^7869721 is an apocalyptic number.

It is an amenable number.

7869721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7869721 is an equidigital number, since it uses as much as digits as its factorization.

7869721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 40.

The square root of 7869721 is about 2805.3023010007. The cubic root of 7869721 is about 198.9083944934.

The spelling of 7869721 in words is "seven million, eight hundred sixty-nine thousand, seven hundred twenty-one".