1398978 has 32 divisors (see below), whose sum is σ = 3553920. Its totient is φ = 399600.

The previous prime is 1398977. The next prime is 1398979. The reversal of 1398978 is 8798931.

It is an interprime number because it is at equal distance from previous prime (1398977) and next prime (1398979).

It is not an unprimeable number, because it can be changed into a prime (1398973) 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, 1473 + ... + 2228.

It is an arithmetic number, because the mean of its divisors is an integer number (111060).

2^1398978 is an apocalyptic number.

1398978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1398978 is an abundant number, since it is smaller than the sum of its proper divisors (2154942).

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

1398978 is a wasteful number, since it uses less digits than its factorization.

1398978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3719 (or 3713 counting only the distinct ones).

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

The square root of 1398978 is about 1182.7840039500. The cubic root of 1398978 is about 111.8416661506.

The spelling of 1398978 in words is "one million, three hundred ninety-eight thousand, nine hundred seventy-eight".