1666050391 has 6 divisors (see below), whose sum is σ = 1720028576. Its totient is φ = 1612086900.

The previous prime is 1666050367. The next prime is 1666050409. The reversal of 1666050391 is 1930506661.

It is not a de Polignac number, because 1666050391 - 2¹⁷ = 1665919319 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1666050391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666050091) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 223596 + ... + 230926.

Almost surely, 2^1666050391 is an apocalyptic number.

1666050391 is a deficient number, since it is larger than the sum of its proper divisors (53978185).

1666050391 is an frugal number, since it uses more digits than its factorization.

1666050391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14693 (or 7362 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 1666050391 is about 40817.2805439069. The cubic root of 1666050391 is about 1185.4849483616.

The spelling of 1666050391 in words is "one billion, six hundred sixty-six million, fifty thousand, three hundred ninety-one".