7821209089 has 2 divisors, whose sum is σ = 7821209090. Its totient is φ = 7821209088.

The previous prime is 7821209047. The next prime is 7821209101. The reversal of 7821209089 is 9809021287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5179249089 + 2641960000 = 71967^2 + 51400^2 .

It is a cyclic number.

It is not a de Polignac number, because 7821209089 - 2¹⁷ = 7821078017 is a prime.

It is a super-2 number, since 2×7821209089² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (7821209789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3910604544 + 3910604545.

It is an arithmetic number, because the mean of its divisors is an integer number (3910604545).

Almost surely, 2^7821209089 is an apocalyptic number.

It is an amenable number.

7821209089 is a deficient number, since it is larger than the sum of its proper divisors (1).

7821209089 is an equidigital number, since it uses as much as digits as its factorization.

7821209089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 7821209089 is about 88437.5999730884. The cubic root of 7821209089 is about 1984.9883647248.

The spelling of 7821209089 in words is "seven billion, eight hundred twenty-one million, two hundred nine thousand, eighty-nine".