101989 has 4 divisors (see below), whose sum is σ = 103360. Its totient is φ = 100620.

The previous prime is 101987. The next prime is 101999. The reversal of 101989 is 989101.

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, and also an emirpimes, since its reverse is a distinct semiprime: 989101 = 71 ⋅13931.

It is a cyclic number.

It is not a de Polignac number, because 101989 - 2¹ = 101987 is a prime.

It is a super-2 number, since 2×101989² = 20803512242, 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 (101987) 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, 567 + ... + 724.

It is an arithmetic number, because the mean of its divisors is an integer number (25840).

2¹⁰¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

101989 is a deficient number, since it is larger than the sum of its proper divisors (1371).

101989 is an equidigital number, since it uses as much as digits as its factorization.

101989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1370.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 101989 is about 319.3571668211. The cubic root of 101989 is about 46.7216076279.

The spelling of 101989 in words is "one hundred one thousand, nine hundred eighty-nine".