221675521 has 4 divisors (see below), whose sum is σ = 225858132. Its totient is φ = 217492912.

The previous prime is 221675491. The next prime is 221675533. The reversal of 221675521 is 125576122.

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

It can be written as a sum of positive squares in 2 ways, for example, as 152868496 + 68807025 = 12364^2 + 8295^2 .

It is a cyclic number.

It is not a de Polignac number, because 221675521 - 2²¹ = 219578369 is a prime.

It is a super-2 number, since 2×221675521² = 98280073221242882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221675551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2091226 + ... + 2091331.

It is an arithmetic number, because the mean of its divisors is an integer number (56464533).

It is a Proth number, since it is equal to 6765 ⋅ 2¹⁵ + 1 and 6765 < 2¹⁵.

Almost surely, 2^221675521 is an apocalyptic number.

It is an amenable number.

221675521 is a deficient number, since it is larger than the sum of its proper divisors (4182611).

221675521 is an equidigital number, since it uses as much as digits as its factorization.

221675521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4182610.

The product of its digits is 8400, while the sum is 31.

The square root of 221675521 is about 14888.7716417440. The cubic root of 221675521 is about 605.2097453664.

The spelling of 221675521 in words is "two hundred twenty-one million, six hundred seventy-five thousand, five hundred twenty-one".