1989955 has 16 divisors (see below), whose sum is σ = 2638944. Its totient is φ = 1428480.

The previous prime is 1989947. The next prime is 1989959. The reversal of 1989955 is 5599891.

It is not a de Polignac number, because 1989955 - 2³ = 1989947 is a prime.

Its product of digits (145800) is a multiple of the sum of its prime divisors (486).

It is not an unprimeable number, because it can be changed into a prime (1989959) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5149 + ... + 5521.

It is an arithmetic number, because the mean of its divisors is an integer number (164934).

2^1989955 is an apocalyptic number.

1989955 is a deficient number, since it is larger than the sum of its proper divisors (648989).

1989955 is a wasteful number, since it uses less digits than its factorization.

1989955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486.

The product of its digits is 145800, while the sum is 46.

The square root of 1989955 is about 1410.6576480493. The cubic root of 1989955 is about 125.7808190834.

It can be divided in two parts, 198 and 9955, that added together give a triangular number (10153 = T₁₄₂).

The spelling of 1989955 in words is "one million, nine hundred eighty-nine thousand, nine hundred fifty-five".