1938781 has 8 divisors (see below), whose sum is σ = 2099160. Its totient is φ = 1780032.

The previous prime is 1938773. The next prime is 1938787. The reversal of 1938781 is 1878391.

It can be written as a sum of positive squares in 4 ways, for example, as 695556 + 1243225 = 834^2 + 1115^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1938781 - 2³ = 1938773 is a prime.

It is a super-2 number, since 2×1938781² = 7517743531922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1938781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1938787) 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 in 7 ways as a sum of consecutive naturals, for example, 3555 + ... + 4063.

It is an arithmetic number, because the mean of its divisors is an integer number (262395).

2^1938781 is an apocalyptic number.

It is an amenable number.

1938781 is a deficient number, since it is larger than the sum of its proper divisors (160379).

1938781 is a wasteful number, since it uses less digits than its factorization.

1938781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815.

The product of its digits is 12096, while the sum is 37.

The square root of 1938781 is about 1392.4011634583. The cubic root of 1938781 is about 124.6932424811.

The spelling of 1938781 in words is "one million, nine hundred thirty-eight thousand, seven hundred eighty-one".