8219416921 has 9 divisors (see below), whose sum is σ = 8732990461. Its totient is φ = 7734471232.

The previous prime is 8219416913. The next prime is 8219416943. The reversal of 8219416921 is 1296149128.

The square root of 8219416921 is 90661.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 6012296521 + 2207120400 = 77539^2 + 46980^2 .

It is not a de Polignac number, because 8219416921 - 2³ = 8219416913 is a prime.

It is a super-2 number, since 2×8219416921² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8219416981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1538571 + ... + 1543903.

Almost surely, 2^8219416921 is an apocalyptic number.

8219416921 is the 90661-st square number.

8219416921 is the 45331-st centered octagonal number.

It is an amenable number.

8219416921 is a deficient number, since it is larger than the sum of its proper divisors (513573540).

8219416921 is an frugal number, since it uses more digits than its factorization.

8219416921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10700 (or 5350 counting only the distinct ones).

The product of its digits is 62208, while the sum is 43.

The cubic root of 8219416921 is about 2018.1200789939.

The spelling of 8219416921 in words is "eight billion, two hundred nineteen million, four hundred sixteen thousand, nine hundred twenty-one".