1665691722 has 64 divisors (see below), whose sum is σ = 3935433600. Its totient is φ = 520416000.

The previous prime is 1665691673. The next prime is 1665691733. The reversal of 1665691722 is 2271965661.

1665691722 is a `hidden beast` number, since 1 + 66 + 569 + 1 + 7 + 22 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 226804 + ... + 234032.

It is an arithmetic number, because the mean of its divisors is an integer number (61491150).

Almost surely, 2^1665691722 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1665691722, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1967716800).

1665691722 is an abundant number, since it is smaller than the sum of its proper divisors (2269741878).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1665691722 is a wasteful number, since it uses less digits than its factorization.

1665691722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7508 (or 7502 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 1665691722 is about 40812.8867148601. The cubic root of 1665691722 is about 1185.3998714597.

The spelling of 1665691722 in words is "one billion, six hundred sixty-five million, six hundred ninety-one thousand, seven hundred twenty-two".