1659631666 has 24 divisors (see below), whose sum is σ = 3159152496. Its totient is φ = 646609320.

The previous prime is 1659631663. The next prime is 1659631669. The reversal of 1659631666 is 6661369561.

It is an interprime number because it is at equal distance from previous prime (1659631663) and next prime (1659631669).

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (1659631663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 768696 + ... + 770851.

It is an arithmetic number, because the mean of its divisors is an integer number (131631354).

Almost surely, 2^1659631666 is an apocalyptic number.

1659631666 is a deficient number, since it is larger than the sum of its proper divisors (1499520830).

1659631666 is a wasteful number, since it uses less digits than its factorization.

1659631666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1539574 (or 1539567 counting only the distinct ones).

The product of its digits is 1049760, while the sum is 49.

The square root of 1659631666 is about 40738.5771229188. The cubic root of 1659631666 is about 1183.9605657254.

The spelling of 1659631666 in words is "one billion, six hundred fifty-nine million, six hundred thirty-one thousand, six hundred sixty-six".