1216423220 has 12 divisors (see below), whose sum is σ = 2554488804. Its totient is φ = 486569280.

The previous prime is 1216423217. The next prime is 1216423249. The reversal of 1216423220 is 223246121.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 125574436 + 1090848784 = 11206^2 + 33028^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30410561 + ... + 30410600.

It is an arithmetic number, because the mean of its divisors is an integer number (212874067).

Almost surely, 2^1216423220 is an apocalyptic number.

1216423220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1216423220 is an abundant number, since it is smaller than the sum of its proper divisors (1338065584).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1216423220 is a wasteful number, since it uses less digits than its factorization.

1216423220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60821170 (or 60821168 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 1216423220 is about 34877.2593533380. The cubic root of 1216423220 is about 1067.4844741767.

Adding to 1216423220 its reverse (223246121), we get a palindrome (1439669341).

The spelling of 1216423220 in words is "one billion, two hundred sixteen million, four hundred twenty-three thousand, two hundred twenty".