1661456305 has 4 divisors (see below), whose sum is σ = 1993747572. Its totient is φ = 1329165040.

The previous prime is 1661456287. The next prime is 1661456309. The reversal of 1661456305 is 5036541661.

1661456305 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 662959504 + 998496801 = 25748^2 + 31599^2 .

It is not a de Polignac number, because 1661456305 - 2⁹ = 1661455793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661456309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166145626 + ... + 166145635.

It is an arithmetic number, because the mean of its divisors is an integer number (498436893).

Almost surely, 2^1661456305 is an apocalyptic number.

It is an amenable number.

1661456305 is a deficient number, since it is larger than the sum of its proper divisors (332291267).

1661456305 is an equidigital number, since it uses as much as digits as its factorization.

1661456305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332291266.

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 1661456305 is about 40760.9654571626. The cubic root of 1661456305 is about 1184.3942983932.

Adding to 1661456305 its reverse (5036541661), we get a palindrome (6697997966).

The spelling of 1661456305 in words is "one billion, six hundred sixty-one million, four hundred fifty-six thousand, three hundred five".