1389978 has 48 divisors (see below), whose sum is σ = 3234816. Its totient is φ = 430560.

The previous prime is 1389961. The next prime is 1389989. The reversal of 1389978 is 8799831.

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26200 + ... + 26252.

It is an arithmetic number, because the mean of its divisors is an integer number (67392).

2^1389978 is an apocalyptic number.

1389978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1389978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1617408).

1389978 is an abundant number, since it is smaller than the sum of its proper divisors (1844838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1389978 is a wasteful number, since it uses less digits than its factorization.

1389978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139 (or 136 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 1389978 is about 1178.9732821400. The cubic root of 1389978 is about 111.6013142020.

The spelling of 1389978 in words is "one million, three hundred eighty-nine thousand, nine hundred seventy-eight".