311221664 has 48 divisors (see below), whose sum is σ = 664410600. Its totient is φ = 142648320.

The previous prime is 311221663. The next prime is 311221681. The reversal of 311221664 is 466122113.

It can be written as a sum of positive squares in 4 ways, for example, as 220819600 + 90402064 = 14860^2 + 9508^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (311221661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59474 + ... + 64494.

Almost surely, 2^311221664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 311221664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (332205300).

311221664 is an abundant number, since it is smaller than the sum of its proper divisors (353188936).

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

311221664 is a wasteful number, since it uses less digits than its factorization.

311221664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5193 (or 5185 counting only the distinct ones).

The product of its digits is 1728, while the sum is 26.

The square root of 311221664 is about 17641.4756752376. The cubic root of 311221664 is about 677.6778228145.

Adding to 311221664 its reverse (466122113), we get a palindrome (777343777).

The spelling of 311221664 in words is "three hundred eleven million, two hundred twenty-one thousand, six hundred sixty-four".