1978111 has 2 divisors, whose sum is σ = 1978112. Its totient is φ = 1978110.

The previous prime is 1978091. The next prime is 1978117. The reversal of 1978111 is 1118791.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1978111 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1978111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1978117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989055 + 989056.

It is an arithmetic number, because the mean of its divisors is an integer number (989056).

2^1978111 is an apocalyptic number.

1978111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978111 is an equidigital number, since it uses as much as digits as its factorization.

1978111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 504, while the sum is 28.

The square root of 1978111 is about 1406.4533408542. The cubic root of 1978111 is about 125.5307776771.

The spelling of 1978111 in words is "one million, nine hundred seventy-eight thousand, one hundred eleven".