7881385 has 4 divisors (see below), whose sum is σ = 9457668. Its totient is φ = 6305104.

The previous prime is 7881373. The next prime is 7881487. The reversal of 7881385 is 5831887.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1058841 + 6822544 = 1029^2 + 2612^2 .

It is a cyclic number.

It is not a de Polignac number, because 7881385 - 2¹⁷ = 7750313 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 788134 + ... + 788143.

It is an arithmetic number, because the mean of its divisors is an integer number (2364417).

Almost surely, 2^7881385 is an apocalyptic number.

It is an amenable number.

7881385 is a deficient number, since it is larger than the sum of its proper divisors (1576283).

7881385 is a wasteful number, since it uses less digits than its factorization.

7881385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1576282.

The product of its digits is 53760, while the sum is 40.

The square root of 7881385 is about 2807.3804515954. The cubic root of 7881385 is about 199.0066157746.

The spelling of 7881385 in words is "seven million, eight hundred eighty-one thousand, three hundred eighty-five".