12221999 has 4 divisors (see below), whose sum is σ = 12369336. Its totient is φ = 12074664.

The previous prime is 12221981. The next prime is 12222013. The reversal of 12221999 is 99912221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99912221 = 29 ⋅3445249.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12221999 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 (12221969) 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, 73544 + ... + 73709.

It is an arithmetic number, because the mean of its divisors is an integer number (3092334).

Almost surely, 2^12221999 is an apocalyptic number.

12221999 is a deficient number, since it is larger than the sum of its proper divisors (147337).

12221999 is an equidigital number, since it uses as much as digits as its factorization.

12221999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147336.

The product of its digits is 5832, while the sum is 35.

The square root of 12221999 is about 3495.9975686490. The cubic root of 12221999 is about 230.3460386645.

The spelling of 12221999 in words is "twelve million, two hundred twenty-one thousand, nine hundred ninety-nine".