1666818651 has 8 divisors (see below), whose sum is σ = 2229436944. Its totient is φ = 1107706400.

The previous prime is 1666818641. The next prime is 1666818653. The reversal of 1666818651 is 1568186661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1666818651 - 2⁵ = 1666818619 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1666818651.

It is not an unprimeable number, because it can be changed into a prime (1666818653) 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, 875400 + ... + 877301.

It is an arithmetic number, because the mean of its divisors is an integer number (278679618).

Almost surely, 2^1666818651 is an apocalyptic number.

1666818651 is a deficient number, since it is larger than the sum of its proper divisors (562618293).

1666818651 is a wasteful number, since it uses less digits than its factorization.

1666818651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1753021.

The product of its digits is 414720, while the sum is 48.

The square root of 1666818651 is about 40826.6904242800. The cubic root of 1666818651 is about 1185.6671398718.

The spelling of 1666818651 in words is "one billion, six hundred sixty-six million, eight hundred eighteen thousand, six hundred fifty-one".