221719681 has 4 divisors (see below), whose sum is σ = 221875200. Its totient is φ = 221564164.

The previous prime is 221719679. The next prime is 221719691. The reversal of 221719681 is 186917122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221719681 - 2¹ = 221719679 is a prime.

It is a super-2 number, since 2×221719681² = 98319233885483522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221719681.

It is not an unprimeable number, because it can be changed into a prime (221719621) 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 3 ways as a sum of consecutive naturals, for example, 75601 + ... + 78478.

It is an arithmetic number, because the mean of its divisors is an integer number (55468800).

Almost surely, 2^221719681 is an apocalyptic number.

It is an amenable number.

221719681 is a deficient number, since it is larger than the sum of its proper divisors (155519).

221719681 is a wasteful number, since it uses less digits than its factorization.

221719681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155518.

The product of its digits is 12096, while the sum is 37.

The square root of 221719681 is about 14890.2545646473. The cubic root of 221719681 is about 605.2499306603.

The spelling of 221719681 in words is "two hundred twenty-one million, seven hundred nineteen thousand, six hundred eighty-one".