1665606642 has 32 divisors (see below), whose sum is σ = 3808897152. Its totient is φ = 475663104.

The previous prime is 1665606641. The next prime is 1665606653. The reversal of 1665606642 is 2466065661.

It is a happy number.

It is a super-3 number, since 3×1665606642³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 1665606594 and 1665606603.

It is not an unprimeable number, because it can be changed into a prime (1665606641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94218 + ... + 110490.

It is an arithmetic number, because the mean of its divisors is an integer number (119028036).

Almost surely, 2^1665606642 is an apocalyptic number.

1665606642 is an abundant number, since it is smaller than the sum of its proper divisors (2143290510).

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

1665606642 is a wasteful number, since it uses less digits than its factorization.

1665606642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18722.

The product of its (nonzero) digits is 311040, while the sum is 42.

The square root of 1665606642 is about 40811.8443837080. The cubic root of 1665606642 is about 1185.3796885457.

The spelling of 1665606642 in words is "one billion, six hundred sixty-five million, six hundred six thousand, six hundred forty-two".