1661105065 has 16 divisors (see below), whose sum is σ = 2100978000. Its totient is φ = 1258845952.

The previous prime is 1661105053. The next prime is 1661105081. The reversal of 1661105065 is 5605011661.

It can be written as a sum of positive squares in 8 ways, for example, as 41203561 + 1619901504 = 6419^2 + 40248^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661105065 - 2⁹ = 1661104553 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100390 + ... + 115759.

It is an arithmetic number, because the mean of its divisors is an integer number (131311125).

Almost surely, 2^1661105065 is an apocalyptic number.

It is an amenable number.

1661105065 is a deficient number, since it is larger than the sum of its proper divisors (439872935).

1661105065 is a wasteful number, since it uses less digits than its factorization.

1661105065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216236.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 1661105065 is about 40756.6566955632. The cubic root of 1661105065 is about 1184.3108302593.

The spelling of 1661105065 in words is "one billion, six hundred sixty-one million, one hundred five thousand, sixty-five".