221161220 has 24 divisors (see below), whose sum is σ = 530787264. Its totient is φ = 75826656.

The previous prime is 221161201. The next prime is 221161231. The reversal of 221161220 is 22161122.

It is an unprimeable number.

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, 789722 + ... + 790001.

It is an arithmetic number, because the mean of its divisors is an integer number (22116136).

Almost surely, 2^221161220 is an apocalyptic number.

221161220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221161220 is an abundant number, since it is smaller than the sum of its proper divisors (309626044).

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

221161220 is a wasteful number, since it uses less digits than its factorization.

221161220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1579739 (or 1579737 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 221161220 is about 14871.4901741554. The cubic root of 221161220 is about 604.7413415169.

The spelling of 221161220 in words is "two hundred twenty-one million, one hundred sixty-one thousand, two hundred twenty".