1666535642 has 16 divisors (see below), whose sum is σ = 2525644800. Its totient is φ = 824698032.

The previous prime is 1666535621. The next prime is 1666535659. The reversal of 1666535642 is 2465356661.

It is a junction number, because it is equal to n+sod(n) for n = 1666535593 and 1666535602.

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, 66359 + ... + 87957.

It is an arithmetic number, because the mean of its divisors is an integer number (157852800).

Almost surely, 2^1666535642 is an apocalyptic number.

1666535642 is a deficient number, since it is larger than the sum of its proper divisors (859109158).

1666535642 is a wasteful number, since it uses less digits than its factorization.

1666535642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21997.

The product of its digits is 777600, while the sum is 44.

The square root of 1666535642 is about 40823.2242969612. The cubic root of 1666535642 is about 1185.6000312985.

The spelling of 1666535642 in words is "one billion, six hundred sixty-six million, five hundred thirty-five thousand, six hundred forty-two".