1661673705 has 16 divisors (see below), whose sum is σ = 2696125824. Its totient is φ = 873743360.

The previous prime is 1661673703. The next prime is 1661673743. The reversal of 1661673705 is 5073761661.

It is not a de Polignac number, because 1661673705 - 2¹ = 1661673703 is a prime.

It is a super-2 number, since 2×1661673705² = 5522319003776854050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1661673703) 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, 779064 + ... + 781193.

It is an arithmetic number, because the mean of its divisors is an integer number (168507864).

Almost surely, 2^1661673705 is an apocalyptic number.

1661673705 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1661673705 is a deficient number, since it is larger than the sum of its proper divisors (1034452119).

1661673705 is a wasteful number, since it uses less digits than its factorization.

1661673705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1560336.

The product of its (nonzero) digits is 158760, while the sum is 42.

The square root of 1661673705 is about 40763.6321369919. The cubic root of 1661673705 is about 1184.4459551014.

The spelling of 1661673705 in words is "one billion, six hundred sixty-one million, six hundred seventy-three thousand, seven hundred five".