1978541 has 2 divisors, whose sum is σ = 1978542. Its totient is φ = 1978540.

The previous prime is 1978531. The next prime is 1978567. The reversal of 1978541 is 1458791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1020100 + 958441 = 1010^2 + 979^2 .

It is a cyclic number.

It is not a de Polignac number, because 1978541 - 2¹⁸ = 1716397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1978531) 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 as a sum of consecutive naturals, namely, 989270 + 989271.

It is an arithmetic number, because the mean of its divisors is an integer number (989271).

2^1978541 is an apocalyptic number.

It is an amenable number.

1978541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978541 is an equidigital number, since it uses as much as digits as its factorization.

1978541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 35.

The square root of 1978541 is about 1406.6061993323. The cubic root of 1978541 is about 125.5398729408.

The spelling of 1978541 in words is "one million, nine hundred seventy-eight thousand, five hundred forty-one".