1661600505 has 16 divisors (see below), whose sum is σ = 2659068864. Its totient is φ = 886017600.

The previous prime is 1661600503. The next prime is 1661600561. The reversal of 1661600505 is 5050061661.

It is not a de Polignac number, because 1661600505 - 2¹ = 1661600503 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661600503) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 136155 + ... + 147855.

It is an arithmetic number, because the mean of its divisors is an integer number (166191804).

Almost surely, 2^1661600505 is an apocalyptic number.

1661600505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1661600505 is a deficient number, since it is larger than the sum of its proper divisors (997468359).

1661600505 is a wasteful number, since it uses less digits than its factorization.

1661600505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21176.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 1661600505 is about 40762.7342679561. The cubic root of 1661600505 is about 1184.4285624535.

The spelling of 1661600505 in words is "one billion, six hundred sixty-one million, six hundred thousand, five hundred five".