1666027489 has 27 divisors (see below), whose sum is σ = 2064759507. Its totient is φ = 1344022176.

The previous prime is 1666027481. The next prime is 1666027501. The reversal of 1666027489 is 9847206661.

The square root of 1666027489 is 40817.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1297080225 + 368947264 = 36015^2 + 19208^2 .

It is not a de Polignac number, because 1666027489 - 2³ = 1666027481 is a prime.

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

It is a Duffinian number.

1666027489 is a modest number, since divided by 27489 gives 1666 as remainder.

It is not an unprimeable number, because it can be changed into a prime (1666027481) 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 26 ways as a sum of consecutive naturals, for example, 98001609 + ... + 98001625.

Almost surely, 2^1666027489 is an apocalyptic number.

1666027489 is the 40817-th square number.

1666027489 is the 20409-th centered octagonal number.

It is an amenable number.

1666027489 is a deficient number, since it is larger than the sum of its proper divisors (398732018).

1666027489 is an frugal number, since it uses more digits than its factorization.

1666027489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90 (or 24 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 49.

The cubic root of 1666027489 is about 1185.4795163329.

Multiplying 1666027489 by its sum of digits (49), we get a square (81635346961 = 285719²).

1666027489 divided by its sum of digits (49) gives a square (34000561 = 5831²).

The spelling of 1666027489 in words is "one billion, six hundred sixty-six million, twenty-seven thousand, four hundred eighty-nine".