1978765 has 8 divisors (see below), whose sum is σ = 2383128. Its totient is φ = 1577280.

The previous prime is 1978763. The next prime is 1978771. The reversal of 1978765 is 5678791.

It can be written as a sum of positive squares in 4 ways, for example, as 335241 + 1643524 = 579^2 + 1282^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1978765 - 2¹ = 1978763 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1335 + ... + 2395.

It is an arithmetic number, because the mean of its divisors is an integer number (297891).

2^1978765 is an apocalyptic number.

It is an amenable number.

1978765 is a deficient number, since it is larger than the sum of its proper divisors (404363).

1978765 is a wasteful number, since it uses less digits than its factorization.

1978765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1439.

The product of its digits is 105840, while the sum is 43.

The square root of 1978765 is about 1406.6858213546. The cubic root of 1978765 is about 125.5446104166.

The spelling of 1978765 in words is "one million, nine hundred seventy-eight thousand, seven hundred sixty-five".