1671720709 has 2 divisors, whose sum is σ = 1671720710. Its totient is φ = 1671720708.

The previous prime is 1671720671. The next prime is 1671720727. The reversal of 1671720709 is 9070271761.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1396890625 + 274830084 = 37375^2 + 16578^2 .

It is a cyclic number.

It is not a de Polignac number, because 1671720709 - 2¹³ = 1671712517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1671720409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 835860354 + 835860355.

It is an arithmetic number, because the mean of its divisors is an integer number (835860355).

Almost surely, 2^1671720709 is an apocalyptic number.

It is an amenable number.

1671720709 is a deficient number, since it is larger than the sum of its proper divisors (1).

1671720709 is an equidigital number, since it uses as much as digits as its factorization.

1671720709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37044, while the sum is 40.

The square root of 1671720709 is about 40886.6813155580. The cubic root of 1671720709 is about 1186.8283380898.

The spelling of 1671720709 in words is "one billion, six hundred seventy-one million, seven hundred twenty thousand, seven hundred nine".