221221312399 has 4 divisors (see below), whose sum is σ = 221459441760. Its totient is φ = 220983183040.

The previous prime is 221221312357. The next prime is 221221312421. The reversal of 221221312399 is 993213122122.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221221312399 - 2⁷ = 221221312271 is a prime.

It is a super-2 number, since 2×221221312399² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221312999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119063287 + ... + 119065144.

It is an arithmetic number, because the mean of its divisors is an integer number (55364860440).

Almost surely, 2^221221312399 is an apocalyptic number.

221221312399 is a deficient number, since it is larger than the sum of its proper divisors (238129361).

221221312399 is an equidigital number, since it uses as much as digits as its factorization.

221221312399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238129360.

The product of its digits is 23328, while the sum is 37.

The spelling of 221221312399 in words is "two hundred twenty-one billion, two hundred twenty-one million, three hundred twelve thousand, three hundred ninety-nine".