1978559 has 16 divisors (see below), whose sum is σ = 2280960. Its totient is φ = 1700160.

The previous prime is 1978541. The next prime is 1978567. The reversal of 1978559 is 9558791.

It is a happy number.

It is not a de Polignac number, because 1978559 - 2²⁰ = 929983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22187 + ... + 22275.

It is an arithmetic number, because the mean of its divisors is an integer number (142560).

2^1978559 is an apocalyptic number.

1978559 is a deficient number, since it is larger than the sum of its proper divisors (302401).

1978559 is a wasteful number, since it uses less digits than its factorization.

1978559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190.

The product of its digits is 113400, while the sum is 44.

The square root of 1978559 is about 1406.6125976970. The cubic root of 1978559 is about 125.5402536440.

The spelling of 1978559 in words is "one million, nine hundred seventy-eight thousand, five hundred fifty-nine".