1978398 has 16 divisors (see below), whose sum is σ = 4396560. Its totient is φ = 659448.

The previous prime is 1978393. The next prime is 1978411. The reversal of 1978398 is 8938791.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18265 + ... + 18372.

It is an arithmetic number, because the mean of its divisors is an integer number (274785).

2^1978398 is an apocalyptic number.

1978398 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1978398 is an abundant number, since it is smaller than the sum of its proper divisors (2418162).

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

1978398 is a wasteful number, since it uses less digits than its factorization.

1978398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36648 (or 36642 counting only the distinct ones).

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

The square root of 1978398 is about 1406.5553668448. Note that the first 3 decimals coincide. The cubic root of 1978398 is about 125.5368483831.

It can be divided in two parts, 19783 and 98, that added together give a square (19881 = 141²).

The spelling of 1978398 in words is "one million, nine hundred seventy-eight thousand, three hundred ninety-eight".