1660487989 has 4 divisors (see below), whose sum is σ = 1660913056. Its totient is φ = 1660062924.

The previous prime is 1660487977. The next prime is 1660487993. The reversal of 1660487989 is 9897840661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1660487989 - 2¹⁵ = 1660455221 is a prime.

It is a super-2 number, since 2×1660487989² = 5514440723226528242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660487909) 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, 206619 + ... + 214504.

It is an arithmetic number, because the mean of its divisors is an integer number (415228264).

Almost surely, 2^1660487989 is an apocalyptic number.

It is an amenable number.

1660487989 is a deficient number, since it is larger than the sum of its proper divisors (425067).

1660487989 is an equidigital number, since it uses as much as digits as its factorization.

1660487989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425066.

The product of its (nonzero) digits is 5225472, while the sum is 58.

The square root of 1660487989 is about 40749.0857443452. The cubic root of 1660487989 is about 1184.1641607682.

The spelling of 1660487989 in words is "one billion, six hundred sixty million, four hundred eighty-seven thousand, nine hundred eighty-nine".