1661000245 has 4 divisors (see below), whose sum is σ = 1993200300. Its totient is φ = 1328800192.

The previous prime is 1661000227. The next prime is 1661000287. The reversal of 1661000245 is 5420001661.

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 948270436 + 712729809 = 30794^2 + 26697^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661000245 - 2⁵ = 1661000213 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166100020 + ... + 166100029.

It is an arithmetic number, because the mean of its divisors is an integer number (498300075).

Almost surely, 2^1661000245 is an apocalyptic number.

It is an amenable number.

1661000245 is a deficient number, since it is larger than the sum of its proper divisors (332200055).

1661000245 is an equidigital number, since it uses as much as digits as its factorization.

1661000245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332200054.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 1661000245 is about 40755.3707503686. The cubic root of 1661000245 is about 1184.2859187159.

The spelling of 1661000245 in words is "one billion, six hundred sixty-one million, two hundred forty-five", and thus it is an aban number.