221991855 has 8 divisors (see below), whose sum is σ = 355186992. Its totient is φ = 118395648.

The previous prime is 221991853. The next prime is 221991893. The reversal of 221991855 is 558199122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 221991855 - 2¹ = 221991853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221991853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7399714 + ... + 7399743.

It is an arithmetic number, because the mean of its divisors is an integer number (44398374).

Almost surely, 2^221991855 is an apocalyptic number.

221991855 is a deficient number, since it is larger than the sum of its proper divisors (133195137).

221991855 is a wasteful number, since it uses less digits than its factorization.

221991855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14799465.

The product of its digits is 64800, while the sum is 42.

The square root of 221991855 is about 14899.3910949408. The cubic root of 221991855 is about 605.4974893993.

The spelling of 221991855 in words is "two hundred twenty-one million, nine hundred ninety-one thousand, eight hundred fifty-five".