989639 has 8 divisors (see below), whose sum is σ = 1161888. Its totient is φ = 825120.

The previous prime is 989629. The next prime is 989641. The reversal of 989639 is 936989.

989639 = 207² + 208² + ... + 227².

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 989639 - 2⁴ = 989623 is a prime.

It is a zygodrome in base 2 and base 6.

It is a self number, because there is not a number n which added to its sum of digits gives 989639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (989629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1652 + ... + 2169.

It is an arithmetic number, because the mean of its divisors is an integer number (145236).

2⁹⁸⁹⁶³⁹ is an apocalyptic number.

989639 is a deficient number, since it is larger than the sum of its proper divisors (172249).

989639 is a wasteful number, since it uses less digits than its factorization.

989639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3865.

The product of its digits is 104976, while the sum is 44.

The square root of 989639 is about 994.8060112404. The cubic root of 989639 is about 99.6534336384.

Subtracting from 989639 its reverse (936989), we obtain a triangular number (52650 = T₃₂₄).

The spelling of 989639 in words is "nine hundred eighty-nine thousand, six hundred thirty-nine".