1977818 has 4 divisors (see below), whose sum is σ = 2966730. Its totient is φ = 988908.

The previous prime is 1977817. The next prime is 1977821. The reversal of 1977818 is 8187791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8187791 = 71 ⋅115321.

It can be written as a sum of positive squares in only one way, i.e., 1968409 + 9409 = 1403^2 + 97^2 .

It is a super-2 number, since 2×1977818² = 7823528082248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1977817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494453 + ... + 494456.

2^1977818 is an apocalyptic number.

1977818 is a deficient number, since it is larger than the sum of its proper divisors (988912).

1977818 is an equidigital number, since it uses as much as digits as its factorization.

1977818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 988911.

The product of its digits is 28224, while the sum is 41.

The square root of 1977818 is about 1406.3491742807. The cubic root of 1977818 is about 125.5245794516.

The spelling of 1977818 in words is "one million, nine hundred seventy-seven thousand, eight hundred eighteen".