1978369 has 4 divisors (see below), whose sum is σ = 1986820. Its totient is φ = 1969920.

The previous prime is 1978363. The next prime is 1978393. The reversal of 1978369 is 9638791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9638791 = 359 ⋅26849.

It can be written as a sum of positive squares in 2 ways, for example, as 739600 + 1238769 = 860^2 + 1113^2 .

It is a cyclic number.

It is not a de Polignac number, because 1978369 - 2¹⁷ = 1847297 is a prime.

It is a super-2 number, since 2×1978369² = 7827887800322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1978363) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3864 + ... + 4345.

It is an arithmetic number, because the mean of its divisors is an integer number (496705).

It is a Proth number, since it is equal to 483 ⋅ 2¹² + 1 and 483 < 2¹².

2^1978369 is an apocalyptic number.

It is an amenable number.

1978369 is a deficient number, since it is larger than the sum of its proper divisors (8451).

1978369 is an equidigital number, since it uses as much as digits as its factorization.

1978369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8450.

The product of its digits is 81648, while the sum is 43.

The square root of 1978369 is about 1406.5450579345. The cubic root of 1978369 is about 125.5362349935.

The spelling of 1978369 in words is "one million, nine hundred seventy-eight thousand, three hundred sixty-nine".