1978775 has 6 divisors (see below), whose sum is σ = 2453712. Its totient is φ = 1583000.

The previous prime is 1978771. The next prime is 1978799. The reversal of 1978775 is 5778791.

It is not a de Polignac number, because 1978775 - 2² = 1978771 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 39551 + ... + 39600.

It is an arithmetic number, because the mean of its divisors is an integer number (408952).

2^1978775 is an apocalyptic number.

1978775 is a deficient number, since it is larger than the sum of its proper divisors (474937).

1978775 is an equidigital number, since it uses as much as digits as its factorization.

1978775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79161 (or 79156 counting only the distinct ones).

The product of its digits is 123480, while the sum is 44.

The square root of 1978775 is about 1406.6893758041. The cubic root of 1978775 is about 125.5448219027.

The spelling of 1978775 in words is "one million, nine hundred seventy-eight thousand, seven hundred seventy-five".