1640066666 has 16 divisors (see below), whose sum is σ = 2880118080. Its totient is φ = 685741920.

The previous prime is 1640066663. The next prime is 1640066671. The reversal of 1640066666 is 6666600461.

It is a Harshad number since it is a multiple of its sum of digits (41).

1640066666 is a modest number, since divided by 66666 gives 16400 as remainder.

It is not an unprimeable number, because it can be changed into a prime (1640066663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1428056 + ... + 1429203.

It is an arithmetic number, because the mean of its divisors is an integer number (180007380).

Almost surely, 2^1640066666 is an apocalyptic number.

1640066666 is a deficient number, since it is larger than the sum of its proper divisors (1240051414).

1640066666 is a wasteful number, since it uses less digits than its factorization.

1640066666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2857309.

The product of its (nonzero) digits is 186624, while the sum is 41.

The square root of 1640066666 is about 40497.7365540347. The cubic root of 1640066666 is about 1179.2896869363.

The spelling of 1640066666 in words is "one billion, six hundred forty million, sixty-six thousand, six hundred sixty-six".