1666518956 has 72 divisors (see below), whose sum is σ = 3236244480. Its totient is φ = 749800800.

The previous prime is 1666518943. The next prime is 1666518967. The reversal of 1666518956 is 6598156661.

It is a junction number, because it is equal to n+sod(n) for n = 1666518898 and 1666518907.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2640761 + ... + 2641391.

It is an arithmetic number, because the mean of its divisors is an integer number (44947840).

Almost surely, 2^1666518956 is an apocalyptic number.

It is an amenable number.

1666518956 is a deficient number, since it is larger than the sum of its proper divisors (1569725524).

1666518956 is a wasteful number, since it uses less digits than its factorization.

1666518956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 763 (or 742 counting only the distinct ones).

The product of its digits is 2332800, while the sum is 53.

The square root of 1666518956 is about 40823.0199274870. The cubic root of 1666518956 is about 1185.5960743898.

The spelling of 1666518956 in words is "one billion, six hundred sixty-six million, five hundred eighteen thousand, nine hundred fifty-six".