1605561101 has 4 divisors (see below), whose sum is σ = 1605656832. Its totient is φ = 1605465372.

The previous prime is 1605561071. The next prime is 1605561103. The reversal of 1605561101 is 1011655061.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1605561101 - 2⁶ = 1605561037 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1605561103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15341 + ... + 58706.

It is an arithmetic number, because the mean of its divisors is an integer number (401414208).

Almost surely, 2^1605561101 is an apocalyptic number.

It is an amenable number.

1605561101 is a deficient number, since it is larger than the sum of its proper divisors (95731).

1605561101 is an equidigital number, since it uses as much as digits as its factorization.

1605561101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95730.

The product of its (nonzero) digits is 900, while the sum is 26.

The square root of 1605561101 is about 40069.4534652021. The cubic root of 1605561101 is about 1170.9605915479.

The spelling of 1605561101 in words is "one billion, six hundred five million, five hundred sixty-one thousand, one hundred one".