1897978 has 4 divisors (see below), whose sum is σ = 2846970. Its totient is φ = 948988.

The previous prime is 1897969. The next prime is 1897979. The reversal of 1897978 is 8797981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8797981 = 709 ⋅12409.

It can be written as a sum of positive squares in only one way, i.e., 1896129 + 1849 = 1377^2 + 43^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1897979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 474493 + ... + 474496.

2^1897978 is an apocalyptic number.

1897978 is a deficient number, since it is larger than the sum of its proper divisors (948992).

1897978 is an equidigital number, since it uses as much as digits as its factorization.

1897978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 948991.

The product of its digits is 254016, while the sum is 49.

The square root of 1897978 is about 1377.6712234782. The cubic root of 1897978 is about 123.8122809990.

The spelling of 1897978 in words is "one million, eight hundred ninety-seven thousand, nine hundred seventy-eight".