1821167217 has 24 divisors (see below), whose sum is σ = 2665189800. Its totient is φ = 1198188288.

The previous prime is 1821167203. The next prime is 1821167321. The reversal of 1821167217 is 7127611281.

It can be written as a sum of positive squares in 4 ways, for example, as 120099681 + 1701067536 = 10959^2 + 41244^2 .

It is not a de Polignac number, because 1821167217 - 2¹¹ = 1821165169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1821167717) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 489159 + ... + 492867.

It is an arithmetic number, because the mean of its divisors is an integer number (111049575).

Almost surely, 2^1821167217 is an apocalyptic number.

It is an amenable number.

1821167217 is a deficient number, since it is larger than the sum of its proper divisors (844022583).

1821167217 is a wasteful number, since it uses less digits than its factorization.

1821167217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4417 (or 4414 counting only the distinct ones).

The product of its digits is 9408, while the sum is 36.

The square root of 1821167217 is about 42675.1358170071. The cubic root of 1821167217 is about 1221.1900993288.

Adding to 1821167217 its reverse (7127611281), we get a palindrome (8948778498).

The spelling of 1821167217 in words is "one billion, eight hundred twenty-one million, one hundred sixty-seven thousand, two hundred seventeen".