8165621 has 4 divisors (see below), whose sum is σ = 8520672. Its totient is φ = 7810572.

The previous prime is 8165609. The next prime is 8165629. The reversal of 8165621 is 1265618.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8165621 - 2¹⁴ = 8149237 is a prime.

It is a super-3 number, since 3×8165621³ (a number of 22 digits) contains 333 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8165629) 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, 177491 + ... + 177536.

It is an arithmetic number, because the mean of its divisors is an integer number (2130168).

Almost surely, 2^8165621 is an apocalyptic number.

It is an amenable number.

8165621 is a deficient number, since it is larger than the sum of its proper divisors (355051).

8165621 is a wasteful number, since it uses less digits than its factorization.

8165621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355050.

The product of its digits is 2880, while the sum is 29.

The square root of 8165621 is about 2857.5550738350. Note that the first 3 decimals coincide. The cubic root of 8165621 is about 201.3707586402.

The spelling of 8165621 in words is "eight million, one hundred sixty-five thousand, six hundred twenty-one".