221221644245 has 16 divisors (see below), whose sum is σ = 307044984960. Its totient is φ = 149867191104.

The previous prime is 221221644239. The next prime is 221221644251. The reversal of 221221644245 is 542446122122.

It is an interprime number because it is at equal distance from previous prime (221221644239) and next prime (221221644251).

It is a cyclic number.

It is not a de Polignac number, because 221221644245 - 2³⁶ = 152502167509 is a prime.

It is a super-2 number, since 2×221221644245² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38073110 + ... + 38078919.

It is an arithmetic number, because the mean of its divisors is an integer number (19190311560).

Almost surely, 2^221221644245 is an apocalyptic number.

It is an amenable number.

221221644245 is a deficient number, since it is larger than the sum of its proper divisors (85823340715).

221221644245 is an equidigital number, since it uses as much as digits as its factorization.

221221644245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76152124.

The product of its digits is 61440, while the sum is 35.

Adding to 221221644245 its reverse (542446122122), we get a palindrome (763667766367).

The spelling of 221221644245 in words is "two hundred twenty-one billion, two hundred twenty-one million, six hundred forty-four thousand, two hundred forty-five".