1666365587 has 4 divisors (see below), whose sum is σ = 1668352560. Its totient is φ = 1664378616.

The previous prime is 1666365581. The next prime is 1666365611. The reversal of 1666365587 is 7855636661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1666365587 - 2⁶ = 1666365523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666365581) 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, 992228 + ... + 993905.

It is an arithmetic number, because the mean of its divisors is an integer number (417088140).

Almost surely, 2^1666365587 is an apocalyptic number.

1666365587 is a deficient number, since it is larger than the sum of its proper divisors (1986973).

1666365587 is an equidigital number, since it uses as much as digits as its factorization.

1666365587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1986972.

The product of its digits is 5443200, while the sum is 53.

The square root of 1666365587 is about 40821.1414220622. The cubic root of 1666365587 is about 1185.5597033138.

The spelling of 1666365587 in words is "one billion, six hundred sixty-six million, three hundred sixty-five thousand, five hundred eighty-seven".