1989851 has 4 divisors (see below), whose sum is σ = 2094600. Its totient is φ = 1885104.

The previous prime is 1989847. The next prime is 1989863. The reversal of 1989851 is 1589891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1589891 = 17 ⋅93523.

It is not a de Polignac number, because 1989851 - 2² = 1989847 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1989799 and 1989808.

It is not an unprimeable number, because it can be changed into a prime (1989811) 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, 52346 + ... + 52383.

It is an arithmetic number, because the mean of its divisors is an integer number (523650).

2^1989851 is an apocalyptic number.

1989851 is a deficient number, since it is larger than the sum of its proper divisors (104749).

1989851 is a wasteful number, since it uses less digits than its factorization.

1989851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104748.

The product of its digits is 25920, while the sum is 41.

The square root of 1989851 is about 1410.6207853282. The cubic root of 1989851 is about 125.7786278391.

The spelling of 1989851 in words is "one million, nine hundred eighty-nine thousand, eight hundred fifty-one".