1978159 has 2 divisors, whose sum is σ = 1978160. Its totient is φ = 1978158.

The previous prime is 1978157. The next prime is 1978181. The reversal of 1978159 is 9518791.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1978159 - 2¹ = 1978157 is a prime.

It is a super-2 number, since 2×1978159² = 7826226058562, which contains 22 as substring.

Together with 1978157, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1978153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989079 + 989080.

It is an arithmetic number, because the mean of its divisors is an integer number (989080).

2^1978159 is an apocalyptic number.

1978159 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978159 is an equidigital number, since it uses as much as digits as its factorization.

1978159 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 40.

The square root of 1978159 is about 1406.4704049499. The cubic root of 1978159 is about 125.5317930277.

The spelling of 1978159 in words is "one million, nine hundred seventy-eight thousand, one hundred fifty-nine".