7821385 has 16 divisors (see below), whose sum is σ = 11027520. Its totient is φ = 5250240.

The previous prime is 7821383. The next prime is 7821397. The reversal of 7821385 is 5831287.

It is not a de Polignac number, because 7821385 - 2¹ = 7821383 is a prime.

It is a super-2 number, since 2×7821385² = 122348126636450, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 7821385.

It is not an unprimeable number, because it can be changed into a prime (7821383) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4755 + ... + 6184.

It is an arithmetic number, because the mean of its divisors is an integer number (689220).

Almost surely, 2^7821385 is an apocalyptic number.

It is an amenable number.

7821385 is a deficient number, since it is larger than the sum of its proper divisors (3206135).

7821385 is a wasteful number, since it uses less digits than its factorization.

7821385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10968.

The product of its digits is 13440, while the sum is 34.

The square root of 7821385 is about 2796.6739173525. The cubic root of 7821385 is about 198.5003246425.

The spelling of 7821385 in words is "seven million, eight hundred twenty-one thousand, three hundred eighty-five".