1878721 has 8 divisors (see below), whose sum is σ = 2142504. Its totient is φ = 1632000.

The previous prime is 1878697. The next prime is 1878733. The reversal of 1878721 is 1278781.

1878721 is nontrivially palindromic in base 16.

It can be written as a sum of positive squares in 4 ways, for example, as 18225 + 1860496 = 135^2 + 1364^2 .

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

It is not a de Polignac number, because 1878721 - 2⁵ = 1878689 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1878781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4030 + ... + 4471.

It is an arithmetic number, because the mean of its divisors is an integer number (267813).

2^1878721 is an apocalyptic number.

It is an amenable number.

1878721 is a deficient number, since it is larger than the sum of its proper divisors (263783).

1878721 is a wasteful number, since it uses less digits than its factorization.

1878721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8531.

The product of its digits is 6272, while the sum is 34.

The square root of 1878721 is about 1370.6644374171. The cubic root of 1878721 is about 123.3921211501.

The spelling of 1878721 in words is "one million, eight hundred seventy-eight thousand, seven hundred twenty-one".