1664727387 has 16 divisors (see below), whose sum is σ = 2286506880. Its totient is φ = 1076686400.

The previous prime is 1664727377. The next prime is 1664727391. The reversal of 1664727387 is 7837274661.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1664727387 - 2¹¹ = 1664725339 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1664727307) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15789 + ... + 59822.

It is an arithmetic number, because the mean of its divisors is an integer number (142906680).

Almost surely, 2^1664727387 is an apocalyptic number.

1664727387 is a deficient number, since it is larger than the sum of its proper divisors (621779493).

1664727387 is a wasteful number, since it uses less digits than its factorization.

1664727387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75834.

The product of its digits is 2370816, while the sum is 51.

The square root of 1664727387 is about 40801.0709050633. The cubic root of 1664727387 is about 1185.1710689667.

The spelling of 1664727387 in words is "one billion, six hundred sixty-four million, seven hundred twenty-seven thousand, three hundred eighty-seven".