221165999 has 4 divisors (see below), whose sum is σ = 230781936. Its totient is φ = 211550064.

The previous prime is 221165993. The next prime is 221166007. The reversal of 221165999 is 999561122.

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 221165999 - 2¹² = 221161903 is a prime.

It is a super-2 number, since 2×221165999² = 97828798227336002, which 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 (221165993) 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, 4807934 + ... + 4807979.

It is an arithmetic number, because the mean of its divisors is an integer number (57695484).

Almost surely, 2^221165999 is an apocalyptic number.

221165999 is a deficient number, since it is larger than the sum of its proper divisors (9615937).

221165999 is an equidigital number, since it uses as much as digits as its factorization.

221165999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9615936.

The product of its digits is 87480, while the sum is 44.

The square root of 221165999 is about 14871.6508498552. The cubic root of 221165999 is about 604.7456973710.

The spelling of 221165999 in words is "two hundred twenty-one million, one hundred sixty-five thousand, nine hundred ninety-nine".