1661566041 has 20 divisors (see below), whose sum is σ = 2542636404. Its totient is φ = 1080691200.

The previous prime is 1661566037. The next prime is 1661566051. The reversal of 1661566041 is 1406651661.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 637310025 + 1024256016 = 25245^2 + 32004^2 .

It is not a de Polignac number, because 1661566041 - 2² = 1661566037 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1661565987 and 1661566005.

It is not an unprimeable number, because it can be changed into a prime (1661566021) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 246840 + ... + 253481.

Almost surely, 2^1661566041 is an apocalyptic number.

It is an amenable number.

1661566041 is a deficient number, since it is larger than the sum of its proper divisors (881070363).

1661566041 is an equidigital number, since it uses as much as digits as its factorization.

1661566041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500374 (or 500365 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 1661566041 is about 40762.3115267032. The cubic root of 1661566041 is about 1184.4203734759.

The spelling of 1661566041 in words is "one billion, six hundred sixty-one million, five hundred sixty-six thousand, forty-one".