7921855 has 4 divisors (see below), whose sum is σ = 9506232. Its totient is φ = 6337480.

The previous prime is 7921831. The next prime is 7921861. The reversal of 7921855 is 5581297.

7921855 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5581297 = 47 ⋅118751.

It is not a de Polignac number, because 7921855 - 2¹³ = 7913663 is a prime.

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, 792181 + ... + 792190.

It is an arithmetic number, because the mean of its divisors is an integer number (2376558).

Almost surely, 2^7921855 is an apocalyptic number.

7921855 is a deficient number, since it is larger than the sum of its proper divisors (1584377).

7921855 is a wasteful number, since it uses less digits than its factorization.

7921855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1584376.

The product of its digits is 25200, while the sum is 37.

The square root of 7921855 is about 2814.5790093724. The cubic root of 7921855 is about 199.3466597231.

The spelling of 7921855 in words is "seven million, nine hundred twenty-one thousand, eight hundred fifty-five".