1666727563 has 4 divisors (see below), whose sum is σ = 1682909488. Its totient is φ = 1650545640.

The previous prime is 1666727539. The next prime is 1666727593. The reversal of 1666727563 is 3657276661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3657276661 = 337 ⋅10852453.

It is a cyclic number.

It is not a de Polignac number, because 1666727563 - 2²¹ = 1664630411 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666727593) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8090808 + ... + 8091013.

It is an arithmetic number, because the mean of its divisors is an integer number (420727372).

Almost surely, 2^1666727563 is an apocalyptic number.

1666727563 is a deficient number, since it is larger than the sum of its proper divisors (16181925).

1666727563 is a wasteful number, since it uses less digits than its factorization.

1666727563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16181924.

The product of its digits is 1905120, while the sum is 49.

The square root of 1666727563 is about 40825.5748642931. The cubic root of 1666727563 is about 1185.6455414382.

The spelling of 1666727563 in words is "one billion, six hundred sixty-six million, seven hundred twenty-seven thousand, five hundred sixty-three".