221066431 has 4 divisors (see below), whose sum is σ = 221434864. Its totient is φ = 220698000.

The previous prime is 221066399. The next prime is 221066441. The reversal of 221066431 is 134660122.

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 221066431 - 2⁵ = 221066399 is a prime.

It is a super-2 number, since 2×221066431² = 97740733830155522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221066396 and 221066405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221066441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183315 + ... + 184516.

It is an arithmetic number, because the mean of its divisors is an integer number (55358716).

Almost surely, 2^221066431 is an apocalyptic number.

221066431 is a deficient number, since it is larger than the sum of its proper divisors (368433).

221066431 is an equidigital number, since it uses as much as digits as its factorization.

221066431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368432.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 221066431 is about 14868.3028957578. The cubic root of 221066431 is about 604.6549324282.

The spelling of 221066431 in words is "two hundred twenty-one million, sixty-six thousand, four hundred thirty-one".