221215623445 has 4 divisors (see below), whose sum is σ = 265458748140. Its totient is φ = 176972498752.

The previous prime is 221215623439. The next prime is 221215623449. The reversal of 221215623445 is 544326512122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 544326512122 = 2 ⋅272163256061.

It can be written as a sum of positive squares in 2 ways, for example, as 124861876164 + 96353747281 = 353358^2 + 310409^2 .

It is a cyclic number.

It is not a de Polignac number, because 221215623445 - 2³ = 221215623437 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221215623449) 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, 22121562340 + ... + 22121562349.

It is an arithmetic number, because the mean of its divisors is an integer number (66364687035).

Almost surely, 2^221215623445 is an apocalyptic number.

It is an amenable number.

221215623445 is a deficient number, since it is larger than the sum of its proper divisors (44243124695).

221215623445 is an equidigital number, since it uses as much as digits as its factorization.

221215623445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44243124694.

The product of its digits is 115200, while the sum is 37.

The spelling of 221215623445 in words is "two hundred twenty-one billion, two hundred fifteen million, six hundred twenty-three thousand, four hundred forty-five".