1978355 has 4 divisors (see below), whose sum is σ = 2374032. Its totient is φ = 1582680.

The previous prime is 1978349. The next prime is 1978363. The reversal of 1978355 is 5538791.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-1978355 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 197831 + ... + 197840.

It is an arithmetic number, because the mean of its divisors is an integer number (593508).

2^1978355 is an apocalyptic number.

1978355 is a deficient number, since it is larger than the sum of its proper divisors (395677).

1978355 is an equidigital number, since it uses as much as digits as its factorization.

1978355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395676.

The product of its digits is 37800, while the sum is 38.

The square root of 1978355 is about 1406.5400811921. The cubic root of 1978355 is about 125.5359388722.

The spelling of 1978355 in words is "one million, nine hundred seventy-eight thousand, three hundred fifty-five".