1661685205 has 8 divisors (see below), whose sum is σ = 1994821632. Its totient is φ = 1328815248.

The previous prime is 1661685199. The next prime is 1661685217. The reversal of 1661685205 is 5025861661.

1661685205 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1661685205 - 2³ = 1661685197 is a prime.

It is a super-2 number, since 2×1661685205² = 5522395441031784050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52629 + ... + 78058.

It is an arithmetic number, because the mean of its divisors is an integer number (249352704).

Almost surely, 2^1661685205 is an apocalyptic number.

It is an amenable number.

1661685205 is a deficient number, since it is larger than the sum of its proper divisors (333136427).

1661685205 is a wasteful number, since it uses less digits than its factorization.

1661685205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133235.

The product of its (nonzero) digits is 86400, while the sum is 40.

The square root of 1661685205 is about 40763.7731938544. The cubic root of 1661685205 is about 1184.4486875065.

The spelling of 1661685205 in words is "one billion, six hundred sixty-one million, six hundred eighty-five thousand, two hundred five".