2171665939 has 2 divisors, whose sum is σ = 2171665940. Its totient is φ = 2171665938.

The previous prime is 2171665927. The next prime is 2171665963. The reversal of 2171665939 is 9395661712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2171665939 - 2¹¹ = 2171663891 is a prime.

It is a super-2 number, since 2×2171665939² = 9432265901225503442, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2171665892 and 2171665901.

It is not a weakly prime, because it can be changed into another prime (2171665999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1085832969 + 1085832970.

It is an arithmetic number, because the mean of its divisors is an integer number (1085832970).

Almost surely, 2^2171665939 is an apocalyptic number.

2171665939 is a deficient number, since it is larger than the sum of its proper divisors (1).

2171665939 is an equidigital number, since it uses as much as digits as its factorization.

2171665939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 612360, while the sum is 49.

The square root of 2171665939 is about 46601.1366706865. The cubic root of 2171665939 is about 1294.9838131974.

The spelling of 2171665939 in words is "two billion, one hundred seventy-one million, six hundred sixty-five thousand, nine hundred thirty-nine".