1978989 has 24 divisors (see below), whose sum is σ = 2919840. Its totient is φ = 1190112.

The previous prime is 1978981. The next prime is 1978993. The reversal of 1978989 is 9898791.

It is not a de Polignac number, because 1978989 - 2³ = 1978981 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 46002 + ... + 46044.

It is an arithmetic number, because the mean of its divisors is an integer number (121660).

2^1978989 is an apocalyptic number.

It is an amenable number.

1978989 is a deficient number, since it is larger than the sum of its proper divisors (940851).

1978989 is a wasteful number, since it uses less digits than its factorization.

1978989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121 (or 98 counting only the distinct ones).

The product of its digits is 326592, while the sum is 51.

The square root of 1978989 is about 1406.7654388703. The cubic root of 1978989 is about 125.5493475349.

The spelling of 1978989 in words is "one million, nine hundred seventy-eight thousand, nine hundred eighty-nine".