221161855 has 4 divisors (see below), whose sum is σ = 265394232. Its totient is φ = 176929480.

The previous prime is 221161849. The next prime is 221161861. The reversal of 221161855 is 558161122.

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

It is an interprime number because it is at equal distance from previous prime (221161849) and next prime (221161861).

It is not a de Polignac number, because 221161855 - 2¹⁹ = 220637567 is a prime.

It is a super-2 number, since 2×221161855² = 97825132214082050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22116181 + ... + 22116190.

It is an arithmetic number, because the mean of its divisors is an integer number (66348558).

Almost surely, 2^221161855 is an apocalyptic number.

221161855 is a deficient number, since it is larger than the sum of its proper divisors (44232377).

221161855 is an equidigital number, since it uses as much as digits as its factorization.

221161855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44232376.

The product of its digits is 4800, while the sum is 31.

The square root of 221161855 is about 14871.5115237154. The cubic root of 221161855 is about 604.7419202959.

The spelling of 221161855 in words is "two hundred twenty-one million, one hundred sixty-one thousand, eight hundred fifty-five".