221329987 has 16 divisors (see below), whose sum is σ = 247560192. Its totient is φ = 196882560.

The previous prime is 221329981. The next prime is 221329991. The reversal of 221329987 is 789923122.

It is a cyclic number.

It is not a de Polignac number, because 221329987 - 2⁷ = 221329859 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221329981) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 17778 + ... + 27544.

It is an arithmetic number, because the mean of its divisors is an integer number (15472512).

Almost surely, 2^221329987 is an apocalyptic number.

221329987 is a deficient number, since it is larger than the sum of its proper divisors (26230205).

221329987 is a wasteful number, since it uses less digits than its factorization.

221329987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9858.

The product of its digits is 108864, while the sum is 43.

The square root of 221329987 is about 14877.1632712692. The cubic root of 221329987 is about 604.8951274178.

The spelling of 221329987 in words is "two hundred twenty-one million, three hundred twenty-nine thousand, nine hundred eighty-seven".