1666666644 has 24 divisors (see below), whose sum is σ = 3952642848. Its totient is φ = 546447840.

The previous prime is 1666666637. The next prime is 1666666649. The reversal of 1666666644 is 4466666661.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666666649) 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, 1137702 + ... + 1139165.

It is an arithmetic number, because the mean of its divisors is an integer number (164693452).

Almost surely, 2^1666666644 is an apocalyptic number.

It is an amenable number.

1666666644 is an abundant number, since it is smaller than the sum of its proper divisors (2285976204).

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

1666666644 is a wasteful number, since it uses less digits than its factorization.

1666666644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2276935 (or 2276933 counting only the distinct ones).

The product of its digits is 4478976, while the sum is 51.

The square root of 1666666644 is about 40824.8287687775. The cubic root of 1666666644 is about 1185.6310961218.

The spelling of 1666666644 in words is "one billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred forty-four".