1661443193 has 2 divisors, whose sum is σ = 1661443194. Its totient is φ = 1661443192.

The previous prime is 1661443187. The next prime is 1661443211. The reversal of 1661443193 is 3913441661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1062564409 + 598878784 = 32597^2 + 24472^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661443193 - 2⁴ = 1661443177 is a prime.

It is not a weakly prime, because it can be changed into another prime (1661443183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830721596 + 830721597.

It is an arithmetic number, because the mean of its divisors is an integer number (830721597).

Almost surely, 2^1661443193 is an apocalyptic number.

It is an amenable number.

1661443193 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661443193 is an equidigital number, since it uses as much as digits as its factorization.

1661443193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 38.

The square root of 1661443193 is about 40760.8046166903. The cubic root of 1661443193 is about 1184.3911826891.

The spelling of 1661443193 in words is "one billion, six hundred sixty-one million, four hundred forty-three thousand, one hundred ninety-three".