1666768919 has 2 divisors, whose sum is σ = 1666768920. Its totient is φ = 1666768918.

The previous prime is 1666768907. The next prime is 1666768951. The reversal of 1666768919 is 9198676661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1666768919 - 2¹² = 1666764823 is a prime.

It is a super-2 number, since 2×1666768919² = 5556237258688857122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666768319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833384459 + 833384460.

It is an arithmetic number, because the mean of its divisors is an integer number (833384460).

Almost surely, 2^1666768919 is an apocalyptic number.

1666768919 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666768919 is an equidigital number, since it uses as much as digits as its factorization.

1666768919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5878656, while the sum is 59.

The square root of 1666768919 is about 40826.0813573872. The cubic root of 1666768919 is about 1185.6553477102.

The spelling of 1666768919 in words is "one billion, six hundred sixty-six million, seven hundred sixty-eight thousand, nine hundred nineteen".