221312311 has 16 divisors (see below), whose sum is σ = 252266400. Its totient is φ = 192304000.

The previous prime is 221312303. The next prime is 221312353. The reversal of 221312311 is 113213122.

It is not a de Polignac number, because 221312311 - 2³ = 221312303 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221312011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28785 + ... + 35653.

It is an arithmetic number, because the mean of its divisors is an integer number (15766650).

Almost surely, 2^221312311 is an apocalyptic number.

221312311 is a deficient number, since it is larger than the sum of its proper divisors (30954089).

221312311 is a wasteful number, since it uses less digits than its factorization.

221312311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7010.

The product of its digits is 72, while the sum is 16.

The square root of 221312311 is about 14876.5691945421. The cubic root of 221312311 is about 604.8790241459.

Adding to 221312311 its reverse (113213122), we get a palindrome (334525433).

It can be divided in two parts, 22131 and 2311, that added together give a palindrome (24442).

The spelling of 221312311 in words is "two hundred twenty-one million, three hundred twelve thousand, three hundred eleven".