1989678657 has 8 divisors (see below), whose sum is σ = 2808958176. Its totient is φ = 1248425792.

The previous prime is 1989678643. The next prime is 1989678659. The reversal of 1989678657 is 7568769891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1989678657 - 2¹⁰ = 1989677633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1989678659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19506603 + ... + 19506704.

It is an arithmetic number, because the mean of its divisors is an integer number (351119772).

Almost surely, 2^1989678657 is an apocalyptic number.

1989678657 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1989678657 is a deficient number, since it is larger than the sum of its proper divisors (819279519).

1989678657 is a wasteful number, since it uses less digits than its factorization.

1989678657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39013327.

The product of its digits is 45722880, while the sum is 66.

The square root of 1989678657 is about 44605.8141613848. The cubic root of 1989678657 is about 1257.7499646299.

The spelling of 1989678657 in words is "one billion, nine hundred eighty-nine million, six hundred seventy-eight thousand, six hundred fifty-seven".