1913172309 has 18 divisors (see below), whose sum is σ = 2798976726. Its totient is φ = 1259266320.

The previous prime is 1913172307. The next prime is 1913172329. The reversal of 1913172309 is 9032713191.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 963916209 + 949256100 = 31047^2 + 30810^2 .

It is not a de Polignac number, because 1913172309 - 2¹ = 1913172307 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1913172307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 39139 + ... + 73199.

It is an arithmetic number, because the mean of its divisors is an integer number (155498707).

Almost surely, 2^1913172309 is an apocalyptic number.

It is an amenable number.

1913172309 is a deficient number, since it is larger than the sum of its proper divisors (885804417).

1913172309 is an equidigital number, since it uses as much as digits as its factorization.

1913172309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34225 (or 34143 counting only the distinct ones).

The product of its (nonzero) digits is 10206, while the sum is 36.

The square root of 1913172309 is about 43739.8252054121. The cubic root of 1913172309 is about 1241.4179731484.

The spelling of 1913172309 in words is "one billion, nine hundred thirteen million, one hundred seventy-two thousand, three hundred nine".