749931209 has 2 divisors, whose sum is σ = 749931210. Its totient is φ = 749931208.

The previous prime is 749931191. The next prime is 749931211. The reversal of 749931209 is 902139947.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 471975625 + 277955584 = 21725^2 + 16672^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-749931209 is a prime.

Together with 749931211, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 749931209.

It is not a weakly prime, because it can be changed into another prime (749931229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 374965604 + 374965605.

It is an arithmetic number, because the mean of its divisors is an integer number (374965605).

Almost surely, 2^749931209 is an apocalyptic number.

It is an amenable number.

749931209 is a deficient number, since it is larger than the sum of its proper divisors (1).

749931209 is an equidigital number, since it uses as much as digits as its factorization.

749931209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 122472, while the sum is 44.

The square root of 749931209 is about 27384.8719003759. The cubic root of 749931209 is about 908.5325174461.

The spelling of 749931209 in words is "seven hundred forty-nine million, nine hundred thirty-one thousand, two hundred nine".