817121 has 4 divisors (see below), whose sum is σ = 852672. Its totient is φ = 781572.

The previous prime is 817111. The next prime is 817123. The reversal of 817121 is 121718.

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, and also an emirpimes, since its reverse is a distinct semiprime: 121718 = 2 ⋅60859.

It is a cyclic number.

It is not a de Polignac number, because 817121 - 2¹⁸ = 554977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 817093 and 817102.

It is not an unprimeable number, because it can be changed into a prime (817123) 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, 17741 + ... + 17786.

It is an arithmetic number, because the mean of its divisors is an integer number (213168).

2⁸¹⁷¹²¹ is an apocalyptic number.

It is an amenable number.

817121 is a deficient number, since it is larger than the sum of its proper divisors (35551).

817121 is a wasteful number, since it uses less digits than its factorization.

817121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35550.

The product of its digits is 112, while the sum is 20.

The square root of 817121 is about 903.9474542251. The cubic root of 817121 is about 93.4893464941.

Adding to 817121 its reverse (121718), we get a palindrome (938839).

It can be divided in two parts, 8171 and 21, that added together give a 13-th power (8192 = 2¹³).

The spelling of 817121 in words is "eight hundred seventeen thousand, one hundred twenty-one".