7855921 has 4 divisors (see below), whose sum is σ = 8318052. Its totient is φ = 7393792.

The previous prime is 7855907. The next prime is 7855931. The reversal of 7855921 is 1295587.

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 4928400 + 2927521 = 2220^2 + 1711^2 .

It is a cyclic number.

It is not a de Polignac number, because 7855921 - 2¹¹ = 7853873 is a prime.

It is a Duffinian number.

7855921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (7855931) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231040 + ... + 231073.

It is an arithmetic number, because the mean of its divisors is an integer number (2079513).

Almost surely, 2^7855921 is an apocalyptic number.

It is an amenable number.

7855921 is a deficient number, since it is larger than the sum of its proper divisors (462131).

7855921 is a wasteful number, since it uses less digits than its factorization.

7855921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 462130.

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

The square root of 7855921 is about 2802.8415938115. The cubic root of 7855921 is about 198.7920607684.

The spelling of 7855921 in words is "seven million, eight hundred fifty-five thousand, nine hundred twenty-one".