817416921 has 4 divisors (see below), whose sum is σ = 1089889232. Its totient is φ = 544944612.

The previous prime is 817416893. The next prime is 817416931. The reversal of 817416921 is 129614718.

817416921 is digitally balanced in base 2, 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 a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 817416921 - 2¹⁴ = 817400537 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 817416921.

It is not an unprimeable number, because it can be changed into a prime (817416931) 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, 136236151 + ... + 136236156.

It is an arithmetic number, because the mean of its divisors is an integer number (272472308).

Almost surely, 2^817416921 is an apocalyptic number.

It is an amenable number.

817416921 is a deficient number, since it is larger than the sum of its proper divisors (272472311).

817416921 is a wasteful number, since it uses less digits than its factorization.

817416921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272472310.

The product of its digits is 24192, while the sum is 39.

The square root of 817416921 is about 28590.5040354311. The cubic root of 817416921 is about 935.0063087833.

The spelling of 817416921 in words is "eight hundred seventeen million, four hundred sixteen thousand, nine hundred twenty-one".