70691209 has 2 divisors, whose sum is σ = 70691210. Its totient is φ = 70691208.

The previous prime is 70691207. The next prime is 70691227. The reversal of 70691209 is 90219607.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45158400 + 25532809 = 6720^2 + 5053^2 .

It is an emirp because it is prime and its reverse (90219607) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 70691209 - 2¹ = 70691207 is a prime.

Together with 70691207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (70691207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35345604 + 35345605.

It is an arithmetic number, because the mean of its divisors is an integer number (35345605).

Almost surely, 2^70691209 is an apocalyptic number.

It is an amenable number.

70691209 is a deficient number, since it is larger than the sum of its proper divisors (1).

70691209 is an equidigital number, since it uses as much as digits as its factorization.

70691209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6804, while the sum is 34.

The square root of 70691209 is about 8407.8064321201. The cubic root of 70691209 is about 413.4805986841.

The spelling of 70691209 in words is "seventy million, six hundred ninety-one thousand, two hundred nine".