1221822399 has 48 divisors (see below), whose sum is σ = 2031118848. Its totient is φ = 649712448.

The previous prime is 1221822391. The next prime is 1221822439. The reversal of 1221822399 is 9932281221.

It is not a de Polignac number, because 1221822399 - 2³ = 1221822391 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221822391) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 120214 + ... + 129980.

It is an arithmetic number, because the mean of its divisors is an integer number (42314976).

Almost surely, 2^1221822399 is an apocalyptic number.

1221822399 is a deficient number, since it is larger than the sum of its proper divisors (809296449).

1221822399 is a wasteful number, since it uses less digits than its factorization.

1221822399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9844 (or 9837 counting only the distinct ones).

The product of its digits is 31104, while the sum is 39.

The square root of 1221822399 is about 34954.5762240082. The cubic root of 1221822399 is about 1069.0615112188.

It can be divided in two parts, 1221822 and 399, that added together give a palindrome (1222221).

The spelling of 1221822399 in words is "one billion, two hundred twenty-one million, eight hundred twenty-two thousand, three hundred ninety-nine".